trunk/src/bintrans_alpha.c

/*
 *  Copyright (C) 2004-2005  Anders Gavare.  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions are met:
 *
 *  1. Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *  2. Redistributions in binary form must reproduce the above copyright  
 *     notice, this list of conditions and the following disclaimer in the 
 *     documentation and/or other materials provided with the distribution.
 *  3. The name of the author may not be used to endorse or promote products
 *     derived from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 *  ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 *  IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 *  ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE   
 *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 *  DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 *  OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 *  HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 *  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 *  OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 *  SUCH DAMAGE.
 *
 *
 *  $Id: bintrans_alpha.c,v 1.114 2005/03/22 09:12:04 debug Exp $
 *
 *  Alpha specific code for dynamic binary translation.
 *
 *  See bintrans.c for more information.  Included from bintrans.c.
 *
 *
 *  Some Alpha registers that are reasonable to use:
 *
 *      t5..t7          6..8            3
 *      s0..s6          9..15           7
 *      a1..a5          17..21          5
 *      t8..t11         22..25          4
 *
 *  These can be "mapped" to MIPS registers in the translated code,
 *  except a0 which points to the cpu struct, and t0..t4 (or so)
 *  which are used by the translated code as temporaries.
 *
 *  3 + 7 + 5 + 4 = 19 available registers. Of course, all (except
 *  s0..s6) must be saved when calling external functions, such as
 *  when doing load/store.
 *
 *  Which are the 19 most commonly used MIPS registers? (This will
 *  include the pc, and the "current number of executed translated
 *  instructions.)
 *
 *  The current allocation is as follows:
 *
 *      Alpha:          MIPS:
 *      ------          -----
 *
 *      t5              pc (64-bit)
 *      t6              bintrans_instructions_executed (32-bit int)
 *      t7              a0 (mips register 4)  (64-bit)
 *      t8              a1 (mips register 5)  (64-bit)
 *      t9              s0 (mips register 16)  (64-bit)
 *      t10             table0 cached (for load/store)
 *      t11             v0 (mips register 2)  (64-bit)
 *      s0              delay_slot (32-bit int)
 *      s1              delay_jmpaddr (64-bit)
 *      s2              sp (mips register 29)  (64-bit)
 *      s3              ra (mips register 31)  (64-bit)
 *      s4              t0 (mips register 8)  (64-bit)
 *      s5              t1 (mips register 9)  (64-bit)
 *      s6              t2 (mips register 10)  (64-bit)
 */

#define MIPSREG_PC                      -3
#define MIPSREG_DELAY_SLOT              -2
#define MIPSREG_DELAY_JMPADDR           -1

#define ALPHA_T0                1
#define ALPHA_T1                2
#define ALPHA_T2                3
#define ALPHA_T3                4
#define ALPHA_T4                5
#define ALPHA_T5                6
#define ALPHA_T6                7
#define ALPHA_T7                8
#define ALPHA_S0                9
#define ALPHA_S1                10
#define ALPHA_S2                11
#define ALPHA_S3                12
#define ALPHA_S4                13
#define ALPHA_S5                14
#define ALPHA_S6                15
#define ALPHA_A0                16
#define ALPHA_A1                17
#define ALPHA_A2                18
#define ALPHA_A3                19
#define ALPHA_A4                20
#define ALPHA_A5                21
#define ALPHA_T8                22
#define ALPHA_T9                23
#define ALPHA_T10               24
#define ALPHA_T11               25
#define ALPHA_ZERO              31

static int map_MIPS_to_Alpha[32] = {
        ALPHA_ZERO, -1, ALPHA_T11, -1,          /*  0 .. 3  */
        ALPHA_T7, ALPHA_T8, -1, -1,             /*  4 .. 7  */
        ALPHA_S4, ALPHA_S5, ALPHA_S6, -1,       /*  8 .. 11  */
        -1, -1, -1, -1,                         /*  12 .. 15  */
        ALPHA_T9, -1, -1, -1,                   /*  16 .. 19  */
        -1, -1, -1, -1,                         /*  20 .. 23  */
        -1, -1, -1, -1,                         /*  24 .. 27  */
        -1, ALPHA_S2, -1, ALPHA_S3,             /*  28 .. 31  */
};


struct cpu dummy_cpu;
struct mips_coproc dummy_coproc;
struct vth32_table dummy_vth32_table;

unsigned char bintrans_alpha_imb[32] = {
        0x86, 0x00, 0x00, 0x00,         /*  imb   */
        0x01, 0x80, 0xfa, 0x6b,         /*  ret   */
        0x1f, 0x04, 0xff, 0x47,         /*  nop   */
        0x00, 0x00, 0xfe, 0x2e,         /*  unop  */
        0x1f, 0x04, 0xff, 0x47,         /*  nop   */
        0x00, 0x00, 0xfe, 0x2e,         /*  unop  */
        0x1f, 0x04, 0xff, 0x47,         /*  nop   */
        0x00, 0x00, 0xfe, 0x2e          /*  unop  */
};


/*
 *  bintrans_host_cacheinvalidate()
 *
 *  Invalidate the host's instruction cache. On Alpha, we do this by
 *  executing an imb instruction.
 *
 *  NOTE:  A simple  asm("imb");  would be enough here, but not all
 *  compilers have such simple constructs, so an entire function has to
 *  be written as bintrans_alpha_imb[] above.
 */
static void bintrans_host_cacheinvalidate(unsigned char *p, size_t len)
{
        /*  Long form of ``asm("imb");''  */

        void (*f)(void);
        f = (void *)&bintrans_alpha_imb[0];
        f();
}


/*
 *  lda sp,-128(sp)     some margin
 *  stq ra,0(sp)
 *  stq s0,8(sp)
 *  stq s1,16(sp)
 *  stq s2,24(sp)
 *  stq s3,32(sp)
 *  stq s4,40(sp)
 *  stq s5,48(sp)
 *  stq s6,56(sp)
 *
 *  jsr ra,(a1),<back>
 *  back:
 *
 *  ldq ra,0(sp)
 *  ldq s0,8(sp)
 *  ldq s1,16(sp)
 *  ldq s2,24(sp)
 *  ldq s3,32(sp)
 *  ldq s4,40(sp)
 *  ldq s5,48(sp)
 *  ldq s6,56(sp)
 *  lda sp,128(sp)
 *  ret
 */
/*  note: offsetof (in stdarg.h) could possibly be used, but I'm not sure
    if it will take care of the compiler problems...  */
#define ofs_pc  (((size_t)&dummy_cpu.pc) - ((size_t)&dummy_cpu))
#define ofs_pc_last     (((size_t)&dummy_cpu.cd.mips.pc_last) - ((size_t)&dummy_cpu))
#define ofs_n   (((size_t)&dummy_cpu.cd.mips.bintrans_instructions_executed) - ((size_t)&dummy_cpu))
#define ofs_ds  (((size_t)&dummy_cpu.cd.mips.delay_slot) - ((size_t)&dummy_cpu))
#define ofs_ja  (((size_t)&dummy_cpu.cd.mips.delay_jmpaddr) - ((size_t)&dummy_cpu))
#define ofs_sp  (((size_t)&dummy_cpu.cd.mips.gpr[MIPS_GPR_SP]) - ((size_t)&dummy_cpu))
#define ofs_ra  (((size_t)&dummy_cpu.cd.mips.gpr[MIPS_GPR_RA]) - ((size_t)&dummy_cpu))
#define ofs_a0  (((size_t)&dummy_cpu.cd.mips.gpr[MIPS_GPR_A0]) - ((size_t)&dummy_cpu))
#define ofs_a1  (((size_t)&dummy_cpu.cd.mips.gpr[MIPS_GPR_A1]) - ((size_t)&dummy_cpu))
#define ofs_t0  (((size_t)&dummy_cpu.cd.mips.gpr[MIPS_GPR_T0]) - ((size_t)&dummy_cpu))
#define ofs_t1  (((size_t)&dummy_cpu.cd.mips.gpr[MIPS_GPR_T1]) - ((size_t)&dummy_cpu))
#define ofs_t2  (((size_t)&dummy_cpu.cd.mips.gpr[MIPS_GPR_T2]) - ((size_t)&dummy_cpu))
#define ofs_v0  (((size_t)&dummy_cpu.cd.mips.gpr[MIPS_GPR_V0]) - ((size_t)&dummy_cpu))
#define ofs_s0  (((size_t)&dummy_cpu.cd.mips.gpr[MIPS_GPR_S0]) - ((size_t)&dummy_cpu))
#define ofs_tbl0 (((size_t)&dummy_cpu.cd.mips.vaddr_to_hostaddr_table0) - ((size_t)&dummy_cpu))
#define ofs_c0  ((size_t)&dummy_vth32_table.bintrans_chunks[0] - (size_t)&dummy_vth32_table)
#define ofs_cb (((size_t)&dummy_cpu.cd.mips.chunk_base_address) - (size_t)&dummy_cpu)


static uint32_t bintrans_alpha_loadstore_32bit[19] = {
        /*
         *  t1 = 1023;
         *  t2 = ((a1 >> 22) & t1) * sizeof(void *);
         *  t3 = ((a1 >> 12) & t1) * sizeof(void *);
         *  t1 = a1 & 4095;
         *
         *  f8 1f 5f 20     lda     t1,1023 * 8
         *  83 76 22 4a     srl     a1,19,t2
         *  84 36 21 4a     srl     a1, 9,t3
         *  03 00 62 44     and     t2,t1,t2
         */
        0x205f1ff8,
        0x4a227683,
        0x4a213684,
        0x44620003,

        /*
         *  t10 is vaddr_to_hostaddr_table0
         *
         *  a3 = tbl0[t2]  (load entry from tbl0)
         *  12 04 03 43     addq    t10,t2,a2
         */
        0x43030412,

        /*  04 00 82 44     and     t3,t1,t3  */
        0x44820004,

        /*  00 00 72 a6     ldq     a3,0(a2)  */
        0xa6720000,

        /*  ff 0f 5f 20     lda     t1,4095  */
        0x205f0fff,

        /*
         *  a3 = tbl1[t3]  (load entry from tbl1 (which is a3))
         *  13 04 64 42     addq    a3,t3,a3
         */
        0x42640413,

        /*  02 00 22 46     and     a1,t1,t1  */
        0x46220002,

        /*  00 00 73 a6     ldq     a3,0(a3)  */
        0xa6730000,

        /*  NULL? Then return failure at once.  */
        /*  bne a3, skip  */
        0xf6600003,

        0x243f0000 | (BINTRANS_DONT_RUN_NEXT >> 16),    /*  ldah  t0,256  */
        0x44270407,                                     /*  or      t0,t6,t6  */
        0x6bfa8001,                                     /*  ret  */

        /*  skip:  */

        /*  01 30 60 46     and     a3,0x1,t0  */
        0x46603001,

        /*  Get rid of the lowest bit:  */
        /*  33 05 61 42     subq    a3,t0,a3  */
        0x42610533,

        /*  The rest of the load/store code was written with t3 as the address.  */

        /*  Add the offset within the page:  */
        /*  04 04 62 42     addq    a3,t1,t3  */
        0x42620404,

        0x6be50000              /*  jmp (t4)  */
};

static void (*bintrans_runchunk)(struct cpu *, unsigned char *);

static void (*bintrans_jump_to_32bit_pc)(struct cpu *);

static void (*bintrans_loadstore_32bit)
    (struct cpu *) = (void *)bintrans_alpha_loadstore_32bit;


/*
 *  bintrans_write_quickjump():
 */
static void bintrans_write_quickjump(struct memory *mem,
        unsigned char *quickjump_code, uint32_t chunkoffset)
{
        int ofs;
        uint64_t alpha_addr = chunkoffset +
            (size_t)mem->translation_code_chunk_space;
        uint32_t *a = (uint32_t *)quickjump_code;

        ofs = (alpha_addr - ((size_t)a+4)) / 4;

        /*  printf("chunkoffset=%i, %016llx %016llx %i\n",
            chunkoffset, (long long)alpha_addr, (long long)a, ofs);  */

        if (ofs > -0xfffff && ofs < 0xfffff) {
                *a++ = 0xc3e00000 | (ofs & 0x1fffff);   /*  br <chunk>  */
        }
}


/*
 *  bintrans_write_chunkreturn():
 */
static void bintrans_write_chunkreturn(unsigned char **addrp)
{
        uint32_t *a = (uint32_t *) *addrp;
        *a++ = 0x6bfa8001;      /*  ret  */
        *addrp = (unsigned char *) a;
}


/*
 *  bintrans_write_chunkreturn_fail():
 */
static void bintrans_write_chunkreturn_fail(unsigned char **addrp)
{
        uint32_t *a = (uint32_t *) *addrp;
        /*  00 01 3f 24     ldah    t0,256  */
        /*  07 04 27 44     or      t0,t6,t6  */
        *a++ = 0x243f0000 | (BINTRANS_DONT_RUN_NEXT >> 16);
        *a++ = 0x44270407;
        *a++ = 0x6bfa8001;      /*  ret  */
        *addrp = (unsigned char *) a;
}


/*
 *  bintrans_move_MIPS_reg_into_Alpha_reg():
 */
static void bintrans_move_MIPS_reg_into_Alpha_reg(unsigned char **addrp, int mipsreg, int alphareg)
{
        uint32_t *a = (uint32_t *) *addrp;
        int ofs, alpha_mips_reg;

        switch (mipsreg) {
        case MIPSREG_PC:
                /*  addq t5,0,alphareg  */
                *a++ = 0x40c01400 | alphareg;
                break;
        case MIPSREG_DELAY_SLOT:
                /*  addq s0,0,alphareg  */
                *a++ = 0x41201400 | alphareg;
                break;
        case MIPSREG_DELAY_JMPADDR:
                /*  addq s1,0,alphareg  */
                *a++ = 0x41401400 | alphareg;
                break;
        default:
                alpha_mips_reg = map_MIPS_to_Alpha[mipsreg];
                if (alpha_mips_reg < 0) {
                        ofs = ((size_t)&dummy_cpu.cd.mips.gpr[mipsreg]) - (size_t)&dummy_cpu;
                        /*  ldq alphareg,gpr[mipsreg](a0)  */
                        *a++ = 0xa4100000 | (alphareg << 21) | ofs;
                } else {
                        /*  addq alpha_mips_reg,0,alphareg  */
                        *a++ = 0x40001400 | (alpha_mips_reg << 21) | alphareg;
                }
        }
        *addrp = (unsigned char *) a;
}


/*
 *  bintrans_move_Alpha_reg_into_MIPS_reg():
 */
static void bintrans_move_Alpha_reg_into_MIPS_reg(unsigned char **addrp, int alphareg, int mipsreg)
{
        uint32_t *a = (uint32_t *) *addrp;
        int ofs, alpha_mips_reg;

        switch (mipsreg) {
        case MIPSREG_PC:
                /*  addq alphareg,0,t5  */
                *a++ = 0x40001406 | (alphareg << 21);
                break;
        case MIPSREG_DELAY_SLOT:
                /*  addq alphareg,0,s0  */
                *a++ = 0x40001409 | (alphareg << 21);
                break;
        case MIPSREG_DELAY_JMPADDR:
                /*  addq alphareg,0,s1  */
                *a++ = 0x4000140a | (alphareg << 21);
                break;
        case 0:         /*  the zero register  */
                break;
        default:
                alpha_mips_reg = map_MIPS_to_Alpha[mipsreg];
                if (alpha_mips_reg < 0) {
                        /*  stq alphareg,gpr[mipsreg](a0)  */
                        ofs = ((size_t)&dummy_cpu.cd.mips.gpr[mipsreg]) - (size_t)&dummy_cpu;
                        *a++ = 0xb4100000 | (alphareg << 21) | ofs;
                } else {
                        /*  addq alphareg,0,alpha_mips_reg  */
                        *a++ = 0x40001400 | (alphareg << 21) | alpha_mips_reg;
                }
        }
        *addrp = (unsigned char *) a;
}


/*
 *  bintrans_write_pc_inc():
 */
static void bintrans_write_pc_inc(unsigned char **addrp)
{
        uint32_t *a = (uint32_t *) *addrp;

        /*  lda t6,1(t6)  */
        *a++ = 0x20e70001;

        /*  lda t5,4(t5)  */
        *a++ = 0x20c60004;

        *addrp = (unsigned char *) a;
}


/*
 *  bintrans_write_instruction__addiu_etc():
 */
static int bintrans_write_instruction__addiu_etc(unsigned char **addrp,
        int rt, int rs, int imm, int instruction_type)
{
        uint32_t *a;
        unsigned int uimm;
        int alpha_rs, alpha_rt;

        /*  TODO: overflow detection for ADDI and DADDI  */
        switch (instruction_type) {
        case HI6_ADDI:
        case HI6_DADDI:
                return 0;
        }

        a = (uint32_t *) *addrp;

        if (rt == 0)
                goto rt0;

        uimm = imm & 0xffff;

        alpha_rs = map_MIPS_to_Alpha[rs];
        alpha_rt = map_MIPS_to_Alpha[rt];

        if (uimm == 0 && (instruction_type == HI6_ADDI ||
            instruction_type == HI6_ADDIU || instruction_type == HI6_DADDI ||
            instruction_type == HI6_DADDIU || instruction_type == HI6_ORI)) {
                if (alpha_rs >= 0 && alpha_rt >= 0) {
                        /*  addq rs,0,rt  */
                        *a++ = 0x40001400 | (alpha_rs << 21) | alpha_rt;
                } else {
                        *addrp = (unsigned char *) a;
                        bintrans_move_MIPS_reg_into_Alpha_reg(addrp, rs, ALPHA_T0);
                        bintrans_move_Alpha_reg_into_MIPS_reg(addrp, ALPHA_T0, rt);
                        a = (uint32_t *) *addrp;
                }
                goto rt0;
        }

        if (alpha_rs < 0) {
                /*  ldq t0,"rs"(a0)  */
                *addrp = (unsigned char *) a;
                bintrans_move_MIPS_reg_into_Alpha_reg(addrp, rs, ALPHA_T0);
                a = (uint32_t *) *addrp;
                alpha_rs = ALPHA_T0;
        }

        if (alpha_rt < 0)
                alpha_rt = ALPHA_T0;

        /*  Place the result of the calculation in alpha_rt:  */

        switch (instruction_type) {
        case HI6_ADDIU:
        case HI6_DADDIU:
        case HI6_ADDI:
        case HI6_DADDI:
                if (uimm < 256) {
                        if (instruction_type == HI6_ADDI ||
                            instruction_type == HI6_ADDIU) {
                                /*  addl rs,uimm,rt  */
                                *a++ = 0x40001000 | (alpha_rs << 21)
                                    | (uimm << 13) | alpha_rt;
                        } else {
                                /*  addq rs,uimm,rt  */
                                *a++ = 0x40001400 | (alpha_rs << 21)
                                    | (uimm << 13) | alpha_rt;
                        }
                } else {
                        /*  lda rt,imm(rs)  */
                        *a++ = 0x20000000 | (alpha_rt << 21) | (alpha_rs << 16) | uimm;
                        if (instruction_type == HI6_ADDI ||
                            instruction_type == HI6_ADDIU) {
                                /*  sign extend, 32->64 bits:  addl t0,zero,t0  */
                                *a++ = 0x40001000 | (alpha_rt << 21) | alpha_rt;
                        }
                }
                break;
        case HI6_ANDI:
        case HI6_ORI:
        case HI6_XORI:
                if (uimm >= 256) {
                        /*  lda t1,4660  */
                        *a++ = 0x205f0000 | uimm;
                        if (uimm & 0x8000) {
                                /*  01 00 42 24  ldah t1,1(t1)  <-- if negative only  */
                                *a++ = 0x24420001;
                        }
                }

                switch (instruction_type) {
                case HI6_ANDI:
                        if (uimm < 256) {
                                /*  and rs,uimm,rt  */
                                *a++ = 0x44001000 | (alpha_rs << 21)
                                    | (uimm << 13) | alpha_rt;
                        } else {
                                /*  and rs,t1,rt  */
                                *a++ = 0x44020000 | (alpha_rs << 21) | alpha_rt;
                        }
                        break;
                case HI6_ORI:
                        if (uimm < 256) {
                                /*  or rs,uimm,rt  */
                                *a++ = 0x44001400 | (alpha_rs << 21)
                                    | (uimm << 13) | alpha_rt;
                        } else {
                                /*  or rs,t1,rt  */
                                *a++ = 0x44020400 | (alpha_rs << 21) | alpha_rt;
                        }
                        break;
                case HI6_XORI:
                        if (uimm < 256) {
                                /*  xor rs,uimm,rt  */
                                *a++ = 0x44001800 | (alpha_rs << 21)
                                    | (uimm << 13) | alpha_rt;
                        } else {
                                /*  xor rs,t1,rt  */
                                *a++ = 0x44020800 | (alpha_rs << 21) | alpha_rt;
                        }
                        break;
                }
                break;
        case HI6_SLTI:
        case HI6_SLTIU:
                /*  lda t1,4660  */
                *a++ = 0x205f0000 | uimm;

                switch (instruction_type) {
                case HI6_SLTI:
                        /*  cmplt rs,t1,rt  */
                        *a++ = 0x400209a0 | (alpha_rs << 21) | alpha_rt;
                        break;
                case HI6_SLTIU:
                        /*  cmpult rs,t1,rt  */
                        *a++ = 0x400203a0 | (alpha_rs << 21) | alpha_rt;
                        break;
                }
                break;
        }

        if (alpha_rt == ALPHA_T0) {
                *a++ = 0x5fff041f;      /*  fnop  */
                *addrp = (unsigned char *) a;
                bintrans_move_Alpha_reg_into_MIPS_reg(addrp, ALPHA_T0, rt);
                a = (uint32_t *) *addrp;
        }

rt0:
        *addrp = (unsigned char *) a;
        bintrans_write_pc_inc(addrp);
        return 1;
}


/*
 *  bintrans_write_instruction__addu_etc():
 */
static int bintrans_write_instruction__addu_etc(unsigned char **addrp,
        int rd, int rs, int rt, int sa, int instruction_type)
{
        unsigned char *a, *unmodified = NULL;
        int load64 = 0, store = 1, ofs, alpha_rd = ALPHA_T0;

        alpha_rd = map_MIPS_to_Alpha[rd];
        if (alpha_rd < 0)
                alpha_rd = ALPHA_T0;

        switch (instruction_type) {
        case SPECIAL_DIV:
        case SPECIAL_DIVU:
                return 0;
        }

        switch (instruction_type) {
        case SPECIAL_DADDU:
        case SPECIAL_DSUBU:
        case SPECIAL_OR:
        case SPECIAL_AND:
        case SPECIAL_NOR:
        case SPECIAL_XOR:
        case SPECIAL_DSLL:
        case SPECIAL_DSRL:
        case SPECIAL_DSRA:
        case SPECIAL_DSLL32:
        case SPECIAL_DSRL32:
        case SPECIAL_DSRA32:
        case SPECIAL_SLT:
        case SPECIAL_SLTU:
        case SPECIAL_MOVZ:
        case SPECIAL_MOVN:
                load64 = 1;
        }

        switch (instruction_type) {
        case SPECIAL_MULT:
        case SPECIAL_MULTU:
                if (rd != 0)
                        return 0;
                store = 0;
                break;
        default:
                if (rd == 0)
                        goto rd0;
        }

        a = *addrp;

        if ((instruction_type == SPECIAL_ADDU || instruction_type == SPECIAL_DADDU
            || instruction_type == SPECIAL_OR) && rt == 0) {
                bintrans_move_MIPS_reg_into_Alpha_reg(&a, rs, ALPHA_T0);
                if (!load64) {
                        *a++ = 0x01; *a++ = 0x00; *a++ = 0x3f; *a++ = 0x40;     /*  addl t0,0,t0  */
                }
                bintrans_move_Alpha_reg_into_MIPS_reg(&a, ALPHA_T0, rd);
                *addrp = a;
                goto rd0;
        }

        /*  t0 = rs, t1 = rt  */
        if (load64) {
                bintrans_move_MIPS_reg_into_Alpha_reg(&a, rs, ALPHA_T0);
                bintrans_move_MIPS_reg_into_Alpha_reg(&a, rt, ALPHA_T1);
        } else {
                bintrans_move_MIPS_reg_into_Alpha_reg(&a, rs, ALPHA_T0);
                *a++ = 0x01; *a++ = 0x00; *a++ = 0x3f; *a++ = 0x40;     /*  addl t0,0,t0  */
                bintrans_move_MIPS_reg_into_Alpha_reg(&a, rt, ALPHA_T1);
                *a++ = 0x02; *a++ = 0x10; *a++ = 0x40; *a++ = 0x40;     /*  addl t1,0,t1  */
        }

        switch (instruction_type) {
        case SPECIAL_ADDU:
                *a++ = alpha_rd; *a++ = 0x00; *a++ = 0x22; *a++ = 0x40; /*  addl t0,t1,rd  */
                break;
        case SPECIAL_DADDU:
                *a++ = alpha_rd; *a++ = 0x04; *a++ = 0x22; *a++ = 0x40; /*  addq t0,t1,rd  */
                break;
        case SPECIAL_SUBU:
                *a++ = 0x20 + alpha_rd; *a++ = 0x01; *a++ = 0x22; *a++ = 0x40;  /*  subl t0,t1,t0  */
                break;
        case SPECIAL_DSUBU:
                *a++ = 0x20 + alpha_rd; *a++ = 0x05; *a++ = 0x22; *a++ = 0x40;  /*  subq t0,t1,t0  */
                break;
        case SPECIAL_AND:
                *a++ = alpha_rd; *a++ = 0x00; *a++ = 0x22; *a++ = 0x44; /*  and t0,t1,t0  */
                break;
        case SPECIAL_OR:
                *a++ = alpha_rd; *a++ = 0x04; *a++ = 0x22; *a++ = 0x44; /*  or t0,t1,t0  */
                break;
        case SPECIAL_NOR:
                *a++ = 0x01; *a++ = 0x04; *a++ = 0x22; *a++ = 0x44;     /*  or t0,t1,t0  */
                *a++ = alpha_rd; *a++ = 0x05; *a++ = 0xe1; *a++ = 0x47; /*  not t0,t0  */
                break;
        case SPECIAL_XOR:
                *a++ = alpha_rd; *a++ = 0x08; *a++ = 0x22; *a++ = 0x44; /*  xor t0,t1,t0  */
                break;
        case SPECIAL_SLL:
                *a++ = 0x21; *a++ = 0x17 + ((sa & 7) << 5); *a++ = 0x40 + (sa >> 3); *a++ = 0x48;       /*  sll t1,sa,t0  */
                *a++ = alpha_rd; *a++ = 0x00; *a++ = 0x3f; *a++ = 0x40;     /*  addl t0,0,t0  */
                break;
        case SPECIAL_SLLV:
                /*  rd = rt << (rs&31)  (logical)     t0 = t1 << (t0&31)  */
                *a++ = 0x01; *a++ = 0xf0; *a++ = 0x23; *a++ = 0x44;     /*  and t0,31,t0  */
                *a++ = 0x21; *a++ = 0x07; *a++ = 0x41; *a++ = 0x48;     /*  sll t1,t0,t0  */
                *a++ = alpha_rd; *a++ = 0x00; *a++ = 0x3f; *a++ = 0x40;     /*  addl t0,0,t0  */
                break;
        case SPECIAL_DSLL:
                *a++ = 0x20 + alpha_rd; *a++ = 0x17 + ((sa & 7) << 5); *a++ = 0x40 + (sa >> 3); *a++ = 0x48;    /*  sll t1,sa,t0  */
                break;
        case SPECIAL_DSLL32:
                sa += 32;
                *a++ = 0x20 + alpha_rd; *a++ = 0x17 + ((sa & 7) << 5); *a++ = 0x40 + (sa >> 3); *a++ = 0x48;    /*  sll t1,sa,t0  */
                break;
        case SPECIAL_SRA:
                *a++ = 0x81; *a++ = 0x17 + ((sa & 7) << 5); *a++ = 0x40 + (sa >> 3); *a++ = 0x48;       /*  sra t1,sa,t0  */
                *a++ = alpha_rd; *a++ = 0x00; *a++ = 0x3f; *a++ = 0x40;     /*  addl t0,0,t0  */
                break;
        case SPECIAL_SRAV:
                /*  rd = rt >> (rs&31)  (arithmetic)     t0 = t1 >> (t0&31)  */
                *a++ = 0x01; *a++ = 0xf0; *a++ = 0x23; *a++ = 0x44;     /*  and t0,31,t0  */
                *a++ = 0x81; *a++ = 0x07; *a++ = 0x41; *a++ = 0x48;     /*  sra t1,t0,t0  */
                *a++ = alpha_rd; *a++ = 0x00; *a++ = 0x3f; *a++ = 0x40;     /*  addl t0,0,t0  */
                break;
        case SPECIAL_DSRA:
                *a++ = 0x80 + alpha_rd; *a++ = 0x17 + ((sa & 7) << 5); *a++ = 0x40 + (sa >> 3); *a++ = 0x48;    /*  sra t1,sa,t0  */
                break;
        case SPECIAL_DSRA32:
                sa += 32;
                *a++ = 0x80 + alpha_rd; *a++ = 0x17 + ((sa & 7) << 5); *a++ = 0x40 + (sa >> 3); *a++ = 0x48;    /*  sra t1,sa,t0  */
                break;
        case SPECIAL_SRL:
                *a++ = 0x22; *a++ = 0xf6; *a++ = 0x41; *a++ = 0x48;     /*  zapnot t1,0xf,t1 (use only lowest 32 bits)  */
                /*  Note: bits of sa are distributed among two different bytes.  */
                *a++ = 0x81; *a++ = 0x16 + ((sa & 7) << 5); *a++ = 0x40 + (sa >> 3); *a++ = 0x48;
                *a++ = alpha_rd; *a++ = 0x00; *a++ = 0x3f; *a++ = 0x40;     /*  addl  */
                break;
        case SPECIAL_SRLV:
                /*  rd = rt >> (rs&31)  (logical)     t0 = t1 >> (t0&31)  */
                *a++ = 0x22; *a++ = 0xf6; *a++ = 0x41; *a++ = 0x48;     /*  zapnot t1,0xf,t1 (use only lowest 32 bits)  */
                *a++ = 0x01; *a++ = 0xf0; *a++ = 0x23; *a++ = 0x44;     /*  and t0,31,t0  */
                *a++ = 0x81; *a++ = 0x06; *a++ = 0x41; *a++ = 0x48;     /*  srl t1,t0,t0  */
                *a++ = alpha_rd; *a++ = 0x00; *a++ = 0x3f; *a++ = 0x40;     /*  addl t0,0,t0  */
                break;
        case SPECIAL_DSRL:
                /*  Note: bits of sa are distributed among two different bytes.  */
                *a++ = 0x80 + alpha_rd; *a++ = 0x16 + ((sa & 7) << 5); *a++ = 0x40 + (sa >> 3); *a++ = 0x48;
                break;
        case SPECIAL_DSRL32:
                /*  Note: bits of sa are distributed among two different bytes.  */
                sa += 32;
                *a++ = 0x80 + alpha_rd; *a++ = 0x16 + ((sa & 7) << 5); *a++ = 0x40 + (sa >> 3); *a++ = 0x48;
                break;
        case SPECIAL_SLT:
                *a++ = 0xa0 + alpha_rd; *a++ = 0x09; *a++ = 0x22; *a++ = 0x40;     /*  cmplt t0,t1,t0  */
                break;
        case SPECIAL_SLTU:
                *a++ = 0xa0 + alpha_rd; *a++ = 0x03; *a++ = 0x22; *a++ = 0x40;     /*  cmpult t0,t1,t0  */
                break;
        case SPECIAL_MULT:
        case SPECIAL_MULTU:
                if (instruction_type == SPECIAL_MULTU) {
                        /*  21 f6 21 48     zapnot  t0,0xf,t0  */
                        /*  22 f6 41 48     zapnot  t1,0xf,t1  */
                        *a++ = 0x21; *a++ = 0xf6; *a++ = 0x21; *a++ = 0x48;
                        *a++ = 0x22; *a++ = 0xf6; *a++ = 0x41; *a++ = 0x48;
                }

                /*  03 04 22 4c     mulq    t0,t1,t2  */
                *a++ = 0x03; *a++ = 0x04; *a++ = 0x22; *a++ = 0x4c;

                /*  01 10 60 40     addl    t2,0,t0  */
                *a++ = 0x01; *a++ = 0x10; *a++ = 0x60; *a++ = 0x40;

                ofs = ((size_t)&dummy_cpu.cd.mips.lo) - (size_t)&dummy_cpu;
                *a++ = (ofs & 255); *a++ = (ofs >> 8); *a++ = 0x30; *a++ = 0xb4;

                /*  81 17 64 48     sra     t2,0x20,t0  */
                *a++ = 0x81; *a++ = 0x17; *a++ = 0x64; *a++ = 0x48;
                *a++ = 0x01; *a++ = 0x00; *a++ = 0x3f; *a++ = 0x40;     /*  addl t0,0,t0  */
                ofs = ((size_t)&dummy_cpu.cd.mips.hi) - (size_t)&dummy_cpu;
                *a++ = (ofs & 255); *a++ = (ofs >> 8); *a++ = 0x30; *a++ = 0xb4;
                break;
        case SPECIAL_MOVZ:
                /*  if rt=0 then rd=rs  ==>  if t1!=0 then t0=unmodified else t0=rd  */
                /*  00 00 40 f4     bne     t1,unmodified  */
                unmodified = a;
                *a++ = 0x00; *a++ = 0x00; *a++ = 0x40; *a++ = 0xf4;
                alpha_rd = ALPHA_T0;
                break;
        case SPECIAL_MOVN:
                /*  if rt!=0 then rd=rs  ==>  if t1=0 then t0=unmodified else t0=rd  */
                /*  00 00 40 e4     beq     t1,unmodified  */
                unmodified = a;
                *a++ = 0x00; *a++ = 0x00; *a++ = 0x40; *a++ = 0xe4;
                alpha_rd = ALPHA_T0;
                break;
        }

        if (store && alpha_rd == ALPHA_T0) {
                bintrans_move_Alpha_reg_into_MIPS_reg(&a, ALPHA_T0, rd);
        }

        if (unmodified != NULL)
                *unmodified = ((size_t)a - (size_t)unmodified - 4) / 4;

        *addrp = a;
rd0:
        bintrans_write_pc_inc(addrp);
        return 1;
}


/*
 *  bintrans_write_instruction__branch():
 */
static int bintrans_write_instruction__branch(unsigned char **addrp,
        int instruction_type, int regimm_type, int rt, int rs, int imm)
{
        uint32_t *a, *b, *c = NULL;
        int alpha_rs, alpha_rt, likely = 0, ofs;

        alpha_rs = map_MIPS_to_Alpha[rs];
        alpha_rt = map_MIPS_to_Alpha[rt];

        switch (instruction_type) {
        case HI6_BEQL:
        case HI6_BNEL:
        case HI6_BLEZL:
        case HI6_BGTZL:
                likely = 1;
        }

        /*
         *  t0 = gpr[rt]; t1 = gpr[rs];
         *
         *  50 00 30 a4     ldq     t0,80(a0)
         *  58 00 50 a4     ldq     t1,88(a0)
         */

        switch (instruction_type) {
        case HI6_BEQ:
        case HI6_BNE:
        case HI6_BEQL:
        case HI6_BNEL:
                if (alpha_rt < 0) {
                        bintrans_move_MIPS_reg_into_Alpha_reg(addrp, rt, ALPHA_T0);
                        alpha_rt = ALPHA_T0;
                }
        }

        if (alpha_rs < 0) {
                bintrans_move_MIPS_reg_into_Alpha_reg(addrp, rs, ALPHA_T1);
                alpha_rs = ALPHA_T1;
        }

        a = (uint32_t *) *addrp;

        /*
         *  Compare alpha_rt (t0) and alpha_rs (t1) for equality (BEQ).
         *  If the result was false (equal to zero), then skip a lot
         *  of instructions:
         *
         *  a1 05 22 40     cmpeq   t0,t1,t0
         *  01 00 20 e4     beq     t0,14 <f+0x14>
         */
        b = NULL;
        if ((instruction_type == HI6_BEQ ||
             instruction_type == HI6_BEQL) && rt != rs) {
                /*  cmpeq rt,rs,t0  */
                *a++ = 0x400005a1 | (alpha_rt << 21) | (alpha_rs << 16);
                b = a;
                *a++ = 0xe4200001;      /*  beq  */
        }
        if (instruction_type == HI6_BNE || instruction_type == HI6_BNEL) {
                /*  cmpeq rt,rs,t0  */
                *a++ = 0x400005a1 | (alpha_rt << 21) | (alpha_rs << 16);
                b = a;
                *a++ = 0xf4200001;      /*  bne  */
        }
        if (instruction_type == HI6_BLEZ || instruction_type == HI6_BLEZL) {
                /*  cmple rs,0,t0  */
                *a++ = 0x40001da1 | (alpha_rs << 21);
                b = a;
                *a++ = 0xe4200001;      /*  beq  */
        }
        if (instruction_type == HI6_BGTZ || instruction_type == HI6_BGTZL) {
                /*  cmple rs,0,t0  */
                *a++ = 0x40001da1 | (alpha_rs << 21);
                b = a;
                *a++ = 0xf4200001;      /*  bne  */
        }
        if (instruction_type == HI6_REGIMM && regimm_type == REGIMM_BLTZ) {
                /*  cmplt rs,0,t0  */
                *a++ = 0x400019a1 | (alpha_rs << 21);
                b = a;
                *a++ = 0xe4200001;      /*  beq  */
        }
        if (instruction_type == HI6_REGIMM && regimm_type == REGIMM_BGEZ) {
                *a++ = 0x207fffff;      /*  lda t2,-1  */
                /*  cmple rs,t2,t0  */
                *a++ = 0x40030da1 | (alpha_rs << 21);
                b = a;
                *a++ = 0xf4200001;      /*  bne  */
        }

        /*
         *  Perform the jump by setting cpu->delay_slot = TO_BE_DELAYED
         *  and cpu->delay_jmpaddr = pc + 4 + (imm << 2).
         *
         *  04 00 26 20     lda     t0,4(t5)            add 4
         *  c8 01 5f 20     lda     t1,456
         *  4a 04 41 40     s4addq  t1,t0,s1            s1 = (t1<<2) + t0
         */

        *a++ = 0x20260004;                      /*  lda t0,4(t5)  */
        *a++ = 0x205f0000 | (imm & 0xffff);     /*  lda  */
        *a++ = 0x4041044a;                      /*  s4addq  */

        /*  02 00 3f 21     lda     s0,TO_BE_DELAYED  */
        *a++ = 0x213f0000 | TO_BE_DELAYED;

        /*
         *  Special case:  "likely"-branches:
         */
        if (likely) {
                c = a;
                *a++ = 0xc3e00001;      /*  br delayed_ok  */

                if (b != NULL)
                        *((unsigned char *)b) = ((size_t)a - (size_t)b - 4) / 4;

                /*  cpu->cd.mips.nullify_next = 1;  */
                /*  01 00 3f 20     lda     t0,1  */
                *a++ = 0x203f0001;
                ofs = (size_t)&dummy_cpu.cd.mips.nullify_next - (size_t)&dummy_cpu;
                *a++ = 0xb0300000 | (ofs & 0xffff);

                /*  fail, so that the next instruction is handled manually:  */
                *addrp = (unsigned char *) a;
                bintrans_write_pc_inc(addrp);
                bintrans_write_chunkreturn_fail(addrp);
                a = (uint32_t *) *addrp;

                if (c != NULL)
                        *((unsigned char *)c) = ((size_t)a - (size_t)c - 4) / 4;
        } else {
                /*  Normal (non-likely) exit:  */
                if (b != NULL)
                        *((unsigned char *)b) = ((size_t)a - (size_t)b - 4) / 4;
        }

        *addrp = (unsigned char *) a;
        bintrans_write_pc_inc(addrp);
        return 1;
}


/*
 *  bintrans_write_instruction__jr():
 */
static int bintrans_write_instruction__jr(unsigned char **addrp, int rs, int rd, int special)
{
        uint32_t *a;
        int alpha_rd;

        alpha_rd = map_MIPS_to_Alpha[rd];
        if (alpha_rd < 0)
                alpha_rd = ALPHA_T0;

        /*
         *  Perform the jump by setting cpu->delay_slot = TO_BE_DELAYED
         *  and cpu->delay_jmpaddr = gpr[rs].
         */

        bintrans_move_MIPS_reg_into_Alpha_reg(addrp, rs, ALPHA_S1);

        a = (uint32_t *) *addrp;
        /*  02 00 3f 21     lda     s0,TO_BE_DELAYED  */
        *a++ = 0x213f0000 | TO_BE_DELAYED;
        *addrp = (unsigned char *) a;

        if (special == SPECIAL_JALR && rd != 0) {
                /*  gpr[rd] = retaddr    (pc + 8)  */
                a = (uint32_t *) *addrp;
                /*  lda alpha_rd,8(t5)  */
                *a++ = 0x20060008 | (alpha_rd << 21);
                *addrp = (unsigned char *) a;
                if (alpha_rd == ALPHA_T0)
                        bintrans_move_Alpha_reg_into_MIPS_reg(addrp, ALPHA_T0, rd);
        }

        bintrans_write_pc_inc(addrp);
        return 1;
}


/*
 *  bintrans_write_instruction__jal():
 */
static int bintrans_write_instruction__jal(unsigned char **addrp,
        int imm, int link)
{
        uint32_t *a;

        a = (uint32_t *) *addrp;

        /*  gpr[31] = retaddr   (NOTE: mips register 31 is in alpha reg s3)  */
        if (link) {
                *a++ = 0x21860008;      /*  lda s3,8(t5)  */
        }

        /*  Set the jmpaddr to top 4 bits of pc + lowest 28 bits of imm*4:  */

        /*
         *  imm = 4*imm;
         *  t0 = ((pc + 4) & ~0x0fffffff) | imm;
         *
         *  04 00 26 20     lda     t0,4(t5)    <-- because the jump is from the delay slot
         *  23 01 5f 24     ldah    t1,291
         *  67 45 42 20     lda     t1,17767(t1)
         *  00 f0 7f 24     ldah    t2,-4096
         *  04 00 23 44     and     t0,t2,t3
         *  0a 04 44 44     or      t1,t3,s1
         */
        imm *= 4;
        *a++ = 0x20260004;
        *a++ = 0x245f0000 | ((imm >> 16) + (imm & 0x8000? 1 : 0));
        *a++ = 0x20420000 | (imm & 0xffff);
        *a++ = 0x247ff000;
        *a++ = 0x44230004;
        *a++ = 0x4444040a;

        /*  02 00 3f 21     lda     s0,TO_BE_DELAYED  */
        *a++ = 0x213f0000 | TO_BE_DELAYED;

        /*  If the machine continues executing here, it will return
            to the main loop, which is fine.  */

        *addrp = (unsigned char *) a;
        bintrans_write_pc_inc(addrp);
        return 1;
}


/*
 *  bintrans_write_instruction__delayedbranch():
 */
static int bintrans_write_instruction__delayedbranch(
        struct memory *mem, unsigned char **addrp,
        uint32_t *potential_chunk_p, uint32_t *chunks,
        int only_care_about_chunk_p, int p, int forward)
{
        unsigned char *a, *skip=NULL, *generic64bit;
        int ofs;
        uint64_t alpha_addr, subaddr;

        a = *addrp;

        if (!only_care_about_chunk_p) {
                /*  Skip all of this if there is no branch:  */
                skip = a;
                *a++ = 0; *a++ = 0; *a++ = 0x20; *a++ = 0xe5;  /*  beq s0,skip  */

                /*
                 *  Perform the jump by setting cpu->delay_slot = 0
                 *  and pc = cpu->delay_jmpaddr.
                 */
                /*  00 00 3f 21     lda     s0,0  */
                *a++ = 0; *a++ = 0; *a++ = 0x3f; *a++ = 0x21;

                bintrans_move_MIPS_reg_into_Alpha_reg(&a, MIPSREG_DELAY_JMPADDR, ALPHA_T0);
                bintrans_move_MIPS_reg_into_Alpha_reg(&a, MIPSREG_PC, ALPHA_T3);
                bintrans_move_Alpha_reg_into_MIPS_reg(&a, ALPHA_T0, MIPSREG_PC);
        }

        if (potential_chunk_p == NULL) {
                if (mem->bintrans_32bit_only) {
                        /*  34 12 70 a7     ldq     t12,4660(a0)  */
                        ofs = (size_t)&dummy_cpu.cd.mips.bintrans_jump_to_32bit_pc - (size_t)&dummy_cpu;
                        *a++ = ofs; *a++ = ofs >> 8; *a++ = 0x70; *a++ = 0xa7;

                        /*  00 00 fb 6b     jmp     (t12)  */
                        *a++ = 0; *a++ = 0; *a++ = 0xfb; *a++ = 0x6b;
                } else {
                        /*
                         *  If the highest 32 bits of the address are either
                         *  0x00000000 or 0xffffffff, then the tables used for
                         *  32-bit load/stores can be used.
                         *
                         *  81 16 24 4a     srl     a1,0x20,t0
                         *  03 00 20 e4     beq     t0,14 <ok1>
                         *  01 30 20 40     addl    t0,0x1,t0
                         *  01 00 20 e4     beq     t0,14 <ok1>
                         *  01 00 e0 c3     br      18 <nook>
                         */
                        *a++ = 0x81; *a++ = 0x16; *a++ = 0x24; *a++ = 0x4a;
                        *a++ = 0x03; *a++ = 0x00; *a++ = 0x20; *a++ = 0xe4;
                        *a++ = 0x01; *a++ = 0x30; *a++ = 0x20; *a++ = 0x40;
                        *a++ = 0x01; *a++ = 0x00; *a++ = 0x20; *a++ = 0xe4;
                        generic64bit = a;
                        *a++ = 0x01; *a++ = 0x00; *a++ = 0xe0; *a++ = 0xc3;

                        /*  34 12 70 a7     ldq     t12,4660(a0)  */
                        ofs = (size_t)&dummy_cpu.cd.mips.bintrans_jump_to_32bit_pc - (size_t)&dummy_cpu;
                        *a++ = ofs; *a++ = ofs >> 8; *a++ = 0x70; *a++ = 0xa7;

                        /*  00 00 fb 6b     jmp     (t12)  */
                        *a++ = 0; *a++ = 0; *a++ = 0xfb; *a++ = 0x6b;


                        if (generic64bit != NULL)
                                *generic64bit = ((size_t)a - (size_t)generic64bit - 4) / 4;

                        /*  Not much we can do here if this wasn't to the same
                            physical page...  */

                        *a++ = 0xfc; *a++ = 0xff; *a++ = 0x84; *a++ = 0x20;     /*  lda t3,-4(t3)  */

                        /*
                         *  Compare the old pc (t3) and the new pc (t0). If they are on the
                         *  same virtual page (which means that they are on the same physical
                         *  page), then we can check the right chunk pointer, and if it
                         *  is non-NULL, then we can jump there.  Otherwise just return.
                         *
                         *  00 f0 5f 20     lda     t1,-4096
                         *  01 00 22 44     and     t0,t1,t0
                         *  04 00 82 44     and     t3,t1,t3
                         *  a3 05 24 40     cmpeq   t0,t3,t2
                         *  01 00 60 f4     bne     t2,7c <ok2>
                         *  01 80 fa 6b     ret
                         */
                        *a++ = 0x00; *a++ = 0xf0; *a++ = 0x5f; *a++ = 0x20;     /*  lda  */
                        *a++ = 0x01; *a++ = 0x00; *a++ = 0x22; *a++ = 0x44;     /*  and  */
                        *a++ = 0x04; *a++ = 0x00; *a++ = 0x82; *a++ = 0x44;     /*  and  */
                        *a++ = 0xa3; *a++ = 0x05; *a++ = 0x24; *a++ = 0x40;     /*  cmpeq  */
                        *a++ = 0x01; *a++ = 0x00; *a++ = 0x60; *a++ = 0xf4;     /*  bne  */
                        *a++ = 0x01; *a++ = 0x80; *a++ = 0xfa; *a++ = 0x6b;     /*  ret  */

                        /*  Don't execute too many instructions. (see comment below)  */
                        *a++ = (N_SAFE_BINTRANS_LIMIT-1)&255; *a++ = ((N_SAFE_BINTRANS_LIMIT-1) >> 8)&255;
                                *a++ = 0x5f; *a++ = 0x20;       /*  lda t1,0x1fff */
                        *a++ = 0xa1; *a++ = 0x0d; *a++ = 0xe2; *a++ = 0x40;     /*  cmple t6,t1,t0  */
                        *a++ = 0x01; *a++ = 0x00; *a++ = 0x20; *a++ = 0xf4;     /*  bne  */
                        *a++ = 0x01; *a++ = 0x80; *a++ = 0xfa; *a++ = 0x6b;     /*  ret  */

                        /*  15 bits at a time, which means max 60 bits, but
                            that should be enough. the top 4 bits are probably
                            not used by userland alpha code. (TODO: verify this)  */
                        alpha_addr = (size_t)chunks;
                        subaddr = (alpha_addr >> 45) & 0x7fff;

                        /*
                         *  00 00 3f 20     lda     t0,0
                         *  21 f7 21 48     sll     t0,0xf,t0
                         *  34 12 21 20     lda     t0,4660(t0)
                         *  21 f7 21 48     sll     t0,0xf,t0
                         *  34 12 21 20     lda     t0,4660(t0)
                         *  21 f7 21 48     sll     t0,0xf,t0
                         *  34 12 21 20     lda     t0,4660(t0)
                         */

                        /*  Start with the topmost 15 bits:  */
                        *a++ = (subaddr & 255); *a++ = (subaddr >> 8); *a++ = 0x3f; *a++ = 0x20;
                        *a++ = 0x21; *a++ = 0xf7; *a++ = 0x21; *a++ = 0x48;     /*  sll  */

                        subaddr = (alpha_addr >> 30) & 0x7fff;
                        *a++ = (subaddr & 255); *a++ = (subaddr >> 8); *a++ = 0x21; *a++ = 0x20;
                        *a++ = 0x21; *a++ = 0xf7; *a++ = 0x21; *a++ = 0x48;     /*  sll  */

                        subaddr = (alpha_addr >> 15) & 0x7fff;
                        *a++ = (subaddr & 255); *a++ = (subaddr >> 8); *a++ = 0x21; *a++ = 0x20;
                        *a++ = 0x21; *a++ = 0xf7; *a++ = 0x21; *a++ = 0x48;     /*  sll  */

                        subaddr = alpha_addr & 0x7fff;
                        *a++ = (subaddr & 255); *a++ = (subaddr >> 8); *a++ = 0x21; *a++ = 0x20;

                        /*
                         *  t2 = pc
                         *  t1 = t2 & 0xfff
                         *  t0 += t1
                         *
                         *  ff 0f 5f 20     lda     t1,4095
                         *  02 00 62 44     and     t2,t1,t1
                         *  01 04 22 40     addq    t0,t1,t0
                         */
                        bintrans_move_MIPS_reg_into_Alpha_reg(&a, MIPSREG_PC, ALPHA_T2);
                        *a++ = 0xff; *a++ = 0x0f; *a++ = 0x5f; *a++ = 0x20;     /*  lda  */
                        *a++ = 0x02; *a++ = 0x00; *a++ = 0x62; *a++ = 0x44;     /*  and  */
                        *a++ = 0x01; *a++ = 0x04; *a++ = 0x22; *a++ = 0x40;     /*  addq  */

                        /*
                         *  Load the chunk pointer (actually, a 32-bit offset) into t0.
                         *  If it is zero, then skip the following.
                         *  Add cpu->chunk_base_address to t0.
                         *  Jump to t0.
                         */

                        *a++ = 0x00; *a++ = 0x00; *a++ = 0x21; *a++ = 0xa0;     /*  ldl t0,0(t0)  */
                        *a++ = 0x03; *a++ = 0x00; *a++ = 0x20; *a++ = 0xe4;     /*  beq t0,<skip>  */

                        /*  ldq t2,chunk_base_address(a0)  */
                        ofs = ((size_t)&dummy_cpu.cd.mips.chunk_base_address) - (size_t)&dummy_cpu;
                        *a++ = (ofs & 255); *a++ = (ofs >> 8); *a++ = 0x70; *a++ = 0xa4;
                        /*  addq t0,t2,t0  */
                        *a++ = 0x01; *a++ = 0x04; *a++ = 0x23; *a++ = 0x40;

                        /*  00 00 e1 6b     jmp     (t0)  */
                        *a++ = 0x00; *a++ = 0x00; *a++ = 0xe1; *a++ = 0x6b;     /*  jmp (t0)  */

                        /*  Failure, then return to the main loop.  */
                        *a++ = 0x01; *a++ = 0x80; *a++ = 0xfa; *a++ = 0x6b;     /*  ret  */
                }
        } else {
                /*
                 *  Just to make sure that we don't become too unreliant
                 *  on the main program loop, we need to return every once
                 *  in a while (interrupts etc).
                 *
                 *  Load the "nr of instructions executed" (which is an int)
                 *  and see if it is below a certain threshold. If so, then
                 *  we go on with the fast path (bintrans), otherwise we
                 *  abort by returning.
                 *
                 *  f4 01 5f 20     lda     t1,500  (some low number...)
                 *  a1 0d c2 40     cmple   t6,t1,t0
                 *  01 00 20 f4     bne     t0,14 <f+0x14>
                 */
                if (!only_care_about_chunk_p && !forward) {
                        *a++ = (N_SAFE_BINTRANS_LIMIT-1)&255; *a++ = ((N_SAFE_BINTRANS_LIMIT-1) >> 8)&255;
                                *a++ = 0x5f; *a++ = 0x20;       /*  lda t1,0x1fff */
                        *a++ = 0xa1; *a++ = 0x0d; *a++ = 0xe2; *a++ = 0x40;     /*  cmple t6,t1,t0  */
                        *a++ = 0x01; *a++ = 0x00; *a++ = 0x20; *a++ = 0xf4;     /*  bne  */
                        *a++ = 0x01; *a++ = 0x80; *a++ = 0xfa; *a++ = 0x6b;     /*  ret  */
                }

                /*
                 *  potential_chunk_p points to an "uint32_t".
                 *  If this value is non-NULL, then it is a piece of Alpha
                 *  machine language code corresponding to the address
                 *  we're jumping to. Otherwise, those instructions haven't
                 *  been translated yet, so we have to return to the main
                 *  loop.  (Actually, we have to add cpu->chunk_base_address,
                 *  because the uint32_t is limited to 32-bit offsets.)
                 *
                 *  Case 1:  The value is non-NULL already at translation
                 *           time. Then we can make a direct (fast) native
                 *           Alpha jump to the code chunk.
                 *
                 *  Case 2:  The value was NULL at translation time, then we
                 *           have to check during runtime.
                 */

                /*  Case 1:  */
                /*  printf("%08x ", *potential_chunk_p);  */
                alpha_addr = *potential_chunk_p + (size_t)mem->translation_code_chunk_space;
                ofs = (alpha_addr - ((size_t)a+4)) / 4;
                /*  printf("%016llx %016llx %i\n", (long long)alpha_addr, (long long)a, ofs);  */

                if ((*potential_chunk_p) != 0 && ofs > -0xfffff && ofs < 0xfffff) {
                        *a++ = ofs & 255; *a++ = (ofs >> 8) & 255; *a++ = 0xe0 + ((ofs >> 16) & 0x1f); *a++ = 0xc3;     /*  br <chunk>  */
                } else {
                        /*  Case 2:  */

                        bintrans_register_potential_quick_jump(mem, a, p);

                        /*  15 bits at a time, which means max 60 bits, but
                            that should be enough. the top 4 bits are probably
                            not used by userland alpha code. (TODO: verify this)  */
                        alpha_addr = (size_t)potential_chunk_p;
                        subaddr = (alpha_addr >> 45) & 0x7fff;

                        /*
                         *  00 00 3f 20     lda     t0,0
                         *  21 f7 21 48     sll     t0,0xf,t0
                         *  34 12 21 20     lda     t0,4660(t0)
                         *  21 f7 21 48     sll     t0,0xf,t0
                         *  34 12 21 20     lda     t0,4660(t0)
                         *  21 f7 21 48     sll     t0,0xf,t0
                         *  34 12 21 20     lda     t0,4660(t0)
                         */

                        /*  Start with the topmost 15 bits:  */
                        *a++ = (subaddr & 255); *a++ = (subaddr >> 8); *a++ = 0x3f; *a++ = 0x20;
                        *a++ = 0x21; *a++ = 0xf7; *a++ = 0x21; *a++ = 0x48;     /*  sll  */

                        subaddr = (alpha_addr >> 30) & 0x7fff;
                        *a++ = (subaddr & 255); *a++ = (subaddr >> 8); *a++ = 0x21; *a++ = 0x20;
                        *a++ = 0x21; *a++ = 0xf7; *a++ = 0x21; *a++ = 0x48;     /*  sll  */

                        subaddr = (alpha_addr >> 15) & 0x7fff;
                        *a++ = (subaddr & 255); *a++ = (subaddr >> 8); *a++ = 0x21; *a++ = 0x20;
                        *a++ = 0x21; *a++ = 0xf7; *a++ = 0x21; *a++ = 0x48;     /*  sll  */

                        subaddr = alpha_addr & 0x7fff;
                        *a++ = (subaddr & 255); *a++ = (subaddr >> 8); *a++ = 0x21; *a++ = 0x20;

                        /*
                         *  Load the chunk pointer into t0.
                         *  If it is NULL (zero), then skip the following jump.
                         *  Jump to t0.
                         */
                        *a++ = 0x00; *a++ = 0x00; *a++ = 0x21; *a++ = 0xa0;     /*  ldl t0,0(t0)  */
                        *a++ = 0x03; *a++ = 0x00; *a++ = 0x20; *a++ = 0xe4;     /*  beq t0,<skip>  */

                        /*  ldq t2,chunk_base_address(a0)  */
                        ofs = ((size_t)&dummy_cpu.cd.mips.chunk_base_address) - (size_t)&dummy_cpu;
                        *a++ = (ofs & 255); *a++ = (ofs >> 8); *a++ = 0x70; *a++ = 0xa4;
                        /*  addq t0,t2,t0  */
                        *a++ = 0x01; *a++ = 0x04; *a++ = 0x23; *a++ = 0x40;

                        /*  00 00 e1 6b     jmp     (t0)  */
                        *a++ = 0x00; *a++ = 0x00; *a++ = 0xe1; *a++ = 0x6b;     /*  jmp (t0)  */

                        /*  "Failure", then let's return to the main loop.  */
                        *a++ = 0x01; *a++ = 0x80; *a++ = 0xfa; *a++ = 0x6b;     /*  ret  */
                }
        }

        if (skip != NULL) {
                *skip = ((size_t)a - (size_t)skip - 4) / 4;
                skip ++;
                *skip = (((size_t)a - (size_t)skip - 4) / 4) >> 8;
        }

        *addrp = a;
        return 1;
}


/*
 *  bintrans_write_instruction__loadstore():
 */
static int bintrans_write_instruction__loadstore(
        struct memory *mem, unsigned char **addrp,
        int rt, int imm, int rs, int instruction_type, int bigendian)
{
        unsigned char *a, *fail, *generic64bit = NULL, *generic64bitA = NULL;
        unsigned char *doloadstore = NULL,
            *ok_unaligned_load3, *ok_unaligned_load2, *ok_unaligned_load1;
        uint32_t *b;
        int ofs, alignment, load = 0, alpha_rs, alpha_rt, unaligned = 0;

        /*  TODO: Not yet:  */
        if (instruction_type == HI6_LQ_MDMX || instruction_type == HI6_SQ) {
                return 0;
        }

        switch (instruction_type) {
        case HI6_LQ_MDMX:
        case HI6_LD:
        case HI6_LDL:
        case HI6_LDR:
        case HI6_LWU:
        case HI6_LW:
        case HI6_LWL:
        case HI6_LWR:
        case HI6_LHU:
        case HI6_LH:
        case HI6_LBU:
        case HI6_LB:
                load = 1;
                if (rt == 0)
                        return 0;
        }

        switch (instruction_type) {
        case HI6_LDL:
        case HI6_LDR:
        case HI6_LWL:
        case HI6_LWR:
        case HI6_SDL:
        case HI6_SDR:
        case HI6_SWL:
        case HI6_SWR:
                unaligned = 1;
        }

        a = *addrp;

        /*
         *  a1 = gpr[rs] + imm;
         *
         *  88 08 30 a4     ldq     t0,2184(a0)
         *  34 12 21 22     lda     a1,4660(t0)
         */

        alpha_rs = map_MIPS_to_Alpha[rs];
        if (alpha_rs < 0) {
                bintrans_move_MIPS_reg_into_Alpha_reg(&a, rs, ALPHA_T0);
                alpha_rs = ALPHA_T0;
        }
        *a++ = imm; *a++ = (imm >> 8); *a++ = 0x20 + alpha_rs; *a++ = 0x22;

        alignment = 0;
        switch (instruction_type) {
        case HI6_LQ_MDMX:
        case HI6_SQ:
                alignment = 15;
                break;
        case HI6_LD:
        case HI6_LDL:
        case HI6_LDR:
        case HI6_SD:
        case HI6_SDL:
        case HI6_SDR:
                alignment = 7;
                break;
        case HI6_LW:
        case HI6_LWL:
        case HI6_LWR:
        case HI6_LWU:
        case HI6_SW:
        case HI6_SWL:
        case HI6_SWR:
                alignment = 3;
                break;
        case HI6_LH:
        case HI6_LHU:
        case HI6_SH:
                alignment = 1;
                break;
        }

        if (unaligned) {
                /*
                 *  Unaligned load/store:  Perform the host load/store at
                 *  an aligned address, and then figure out which bytes to
                 *  actually load into the destination register.
                 *
                 *  02 30 20 46     and     a1,alignment,t1
                 *  31 05 22 42     subq    a1,t1,a1
                 */
                *a++ = 0x02; *a++ = 0x10 + alignment * 0x20; *a++ = 0x20 + (alignment >> 3); *a++ = 0x46;
                *a++ = 0x31; *a++ = 0x05; *a++ = 0x22; *a++ = 0x42;
        } else if (alignment > 0) {
                /*
                 *  Check alignment:
                 *
                 *  02 30 20 46     and     a1,0x1,t1
                 *  02 70 20 46     and     a1,0x3,t1   (one of these "and"s)
                 *  02 f0 20 46     and     a1,0x7,t1
                 *  02 f0 21 46     and     a1,0xf,t1
                 *  01 00 40 e4     beq     t1,<okalign>
                 *  01 80 fa 6b     ret
                 */
                *a++ = 0x02; *a++ = 0x10 + alignment * 0x20; *a++ = 0x20 + (alignment >> 3); *a++ = 0x46;
                fail = a;
                *a++ = 0x01; *a++ = 0x00; *a++ = 0x40; *a++ = 0xe4;
                *addrp = a;
                bintrans_write_chunkreturn_fail(addrp);
                a = *addrp;
                *fail = ((size_t)a - (size_t)fail - 4) / 4;
        }

        alpha_rt = map_MIPS_to_Alpha[rt];

        if (mem->bintrans_32bit_only) {
                /*  Special case for 32-bit addressing:  */

                ofs = ((size_t)&dummy_cpu.cd.mips.bintrans_loadstore_32bit) - (size_t)&dummy_cpu;
                /*  ldq t12,bintrans_loadstore_32bit(a0)  */
                *a++ = ofs; *a++ = ofs >> 8; *a++ = 0x70; *a++ = 0xa7;

                /*  jsr t4,(t12),<after>  */
                *a++ = 0x00; *a++ = 0x40; *a++ = 0xbb; *a++ = 0x68;

                /*
                 *  Now:
                 *      a3 = host page
                 *      t0 = 0 for readonly pages, 1 for read/write pages
                 *      t3 = address of host load/store
                 */

                /*  If this is a store, then the lowest bit must be set:  */
                if (!load) {
                        /*  01 00 20 f4     bne     t0,<okzzz>  */
                        fail = a;
                        *a++ = 0x01; *a++ = 0x00; *a++ = 0x20; *a++ = 0xf4;
                        bintrans_write_chunkreturn_fail(&a);
                        *fail = ((size_t)a - (size_t)fail - 4) / 4;
                }
        } else {
                /*
                 *  If the highest 33 bits of the address are either all ones
                 *  or all zeroes, then the tables used for 32-bit load/stores
                 *  can be used.
                 */
                *a++ = 0x81; *a++ = 0xf6; *a++ = 0x23; *a++ = 0x4a;     /*  srl a1,0x1f,t0  */
                *a++ = 0x01; *a++ = 0x30; *a++ = 0x20; *a++ = 0x44;     /*  and t0,0x1,t0  */
                *a++ = 0x04; *a++ = 0x00; *a++ = 0x20; *a++ = 0xe4;     /*  beq t0,<noll>  */
                *a++ = 0x81; *a++ = 0x16; *a++ = 0x24; *a++ = 0x4a;     /*  srl a1,0x20,t0  */
                *a++ = 0x01; *a++ = 0x30; *a++ = 0x20; *a++ = 0x40;     /*  addl t0,0x1,t0  */
                *a++ = 0x04; *a++ = 0x00; *a++ = 0x20; *a++ = 0xe4;     /*  beq t0,<ok>  */
                generic64bit = a;
                *a++ = 0x04; *a++ = 0x00; *a++ = 0xe0; *a++ = 0xc3;     /*  br <generic>  */
                /*  <noll>:  */
                *a++ = 0x81; *a++ = 0x16; *a++ = 0x24; *a++ = 0x4a;     /*  srl a1,0x20,t0  */
                *a++ = 0x01; *a++ = 0x00; *a++ = 0x20; *a++ = 0xe4;     /*  beq t0,<ok>  */
                generic64bitA = a;
                *a++ = 0x04; *a++ = 0x00; *a++ = 0xe0; *a++ = 0xc3;     /*  br <generic>  */

                ofs = ((size_t)&dummy_cpu.cd.mips.bintrans_loadstore_32bit) - (size_t)&dummy_cpu;
                /*  ldq t12,bintrans_loadstore_32bit(a0)  */
                *a++ = ofs; *a++ = ofs >> 8; *a++ = 0x70; *a++ = 0xa7;

                /*  jsr t4,(t12),<after>  */
                *a++ = 0x00; *a++ = 0x40; *a++ = 0xbb; *a++ = 0x68;

                /*
                 *  Now:
                 *      a3 = host page  (or NULL if not found)
                 *      t0 = 0 for readonly pages, 1 for read/write pages
                 *      t3 = (potential) address of host load/store
                 */

                /*  If this is a store, then the lowest bit must be set:  */
                if (!load) {
                        /*  01 00 20 f4     bne     t0,<okzzz>  */
                        fail = a;
                        *a++ = 0x01; *a++ = 0x00; *a++ = 0x20; *a++ = 0xf4;
                        bintrans_write_chunkreturn_fail(&a);
                        *fail = ((size_t)a - (size_t)fail - 4) / 4;
                }

                doloadstore = a;
                *a++ = 0x01; *a++ = 0x00; *a++ = 0xe0; *a++ = 0xc3;


                /*
                 *  Generic (64-bit) load/store:
                 */

                if (generic64bit != NULL)
                        *generic64bit = ((size_t)a - (size_t)generic64bit - 4) / 4;
                if (generic64bitA != NULL)
                        *generic64bitA = ((size_t)a - (size_t)generic64bitA - 4) / 4;

                *addrp = a;
                b = (uint32_t *) *addrp;

                /*  Save a0 and the old return address on the stack:  */
                *b++ = 0x23deff80;              /*  lda sp,-128(sp)  */

                *b++ = 0xb75e0000;              /*  stq ra,0(sp)  */
                *b++ = 0xb61e0008;              /*  stq a0,8(sp)  */
                *b++ = 0xb4de0010;              /*  stq t5,16(sp)  */
                *b++ = 0xb0fe0018;              /*  stl t6,24(sp)  */
                *b++ = 0xb71e0020;              /*  stq t10,32(sp)  */
                *b++ = 0xb73e0028;              /*  stq t11,40(sp)  */
                *b++ = 0xb51e0030;              /*  stq t7,48(sp)  */
                *b++ = 0xb6de0038;              /*  stq t8,56(sp)  */
                *b++ = 0xb6fe0040;              /*  stq t9,64(sp)  */

                ofs = ((size_t)&dummy_cpu.cd.mips.fast_vaddr_to_hostaddr) - (size_t)&dummy_cpu;

                *b++ = 0xa7700000 | ofs;        /*  ldq t12,0(a0)  */

                /*  a1 is already vaddr. set a2 = writeflag  */
                *b++ = 0x225f0000 | (load? 0 : 1);

                /*  Call fast_vaddr_to_hostaddr:  */
                *b++ = 0x6b5b4000;              /*  jsr ra,(t12),<after>  */

                /*  Restore the old return address and a0 from the stack:  */
                *b++ = 0xa75e0000;              /*  ldq ra,0(sp)  */
                *b++ = 0xa61e0008;              /*  ldq a0,8(sp)  */
                *b++ = 0xa4de0010;              /*  ldq t5,16(sp)  */
                *b++ = 0xa0fe0018;              /*  ldl t6,24(sp)  */
                *b++ = 0xa71e0020;              /*  ldq t10,32(sp)  */
                *b++ = 0xa73e0028;              /*  ldq t11,40(sp)  */
                *b++ = 0xa51e0030;              /*  ldq t7,48(sp)  */
                *b++ = 0xa6de0038;              /*  ldq t8,56(sp)  */
                *b++ = 0xa6fe0040;              /*  ldq t9,64(sp)  */

                *b++ = 0x23de0080;              /*  lda sp,128(sp)  */

                *addrp = (unsigned char *) b;
                a = *addrp;

                /*
                 *  NULL? Then return failure.
                 *  01 00 00 f4     bne     v0,f8 <okzz>
                 */
                fail = a;
                *a++ = 0x01; *a++ = 0x00; *a++ = 0x00; *a++ = 0xf4;
                bintrans_write_chunkreturn_fail(&a);
                *fail = ((size_t)a - (size_t)fail - 4) / 4;

                /*  The rest of this code was written with t3 as the address.  */

                /*  04 14 00 40     addq    v0,0,t3  */
                *a++ = 0x04; *a++ = 0x14; *a++ = 0x00; *a++ = 0x40;

                if (doloadstore != NULL)
                        *doloadstore = ((size_t)a - (size_t)doloadstore - 4) / 4;
        }


        switch (instruction_type) {
        case HI6_LQ_MDMX:
                /*  TODO  */
                break;
        case HI6_LD:
                *a++ = 0x00; *a++ = 0x00; *a++ = 0x24; *a++ = 0xa4;                     /*  ldq t0,0(t3)  */
                if (bigendian) {
                        /*  remember original 8 bytes of t0:  */
                        *a++ = 0x05; *a++ = 0x04; *a++ = 0x3f; *a++ = 0x40;             /*  addq t0,zero,t4  */

                        /*  swap lowest 4 bytes:  */
                        *a++ = 0x62; *a++ = 0x71; *a++ = 0x20; *a++ = 0x48;             /*  insbl t0,3,t1  */
                        *a++ = 0xc3; *a++ = 0x30; *a++ = 0x20; *a++ = 0x48;             /*  extbl t0,1,t2  */
                        *a++ = 0x23; *a++ = 0x17; *a++ = 0x62; *a++ = 0x48;             /*  sll t2,16,t2  */
                        *a++ = 0x02; *a++ = 0x04; *a++ = 0x62; *a++ = 0x44;             /*  or t2,t1,t1  */
                        *a++ = 0xc3; *a++ = 0x50; *a++ = 0x20; *a++ = 0x48;             /*  extbl t0,2,t2  */
                        *a++ = 0x23; *a++ = 0x17; *a++ = 0x61; *a++ = 0x48;             /*  sll t2,8,t2  */
                        *a++ = 0x02; *a++ = 0x04; *a++ = 0x62; *a++ = 0x44;             /*  or t2,t1,t1  */
                        *a++ = 0xc3; *a++ = 0x70; *a++ = 0x20; *a++ = 0x48;             /*  extbl t0,3,t2  */
                        *a++ = 0x01; *a++ = 0x04; *a++ = 0x62; *a++ = 0x44;             /*  or t2,t1,t0  */

                        /*  save result in (top 4 bytes of) t1, then t4. get back top bits of t4:  */
                        *a++ = 0x22; *a++ = 0x17; *a++ = 0x24; *a++ = 0x48;             /*  sll t0,0x20,t1  */
                        *a++ = 0x81; *a++ = 0x16; *a++ = 0xa4; *a++ = 0x48;             /*  srl t4,0x20,t0  */
                        *a++ = 0x05; *a++ = 0x14; *a++ = 0x40; *a++ = 0x40;             /*  addq t1,0,t4  */

                        /*  swap highest 4 bytes:  */
                        *a++ = 0x62; *a++ = 0x71; *a++ = 0x20; *a++ = 0x48;             /*  insbl t0,3,t1  */
                        *a++ = 0xc3; *a++ = 0x30; *a++ = 0x20; *a++ = 0x48;             /*  extbl t0,1,t2  */
                        *a++ = 0x23; *a++ = 0x17; *a++ = 0x62; *a++ = 0x48;             /*  sll t2,16,t2  */
                        *a++ = 0x02; *a++ = 0x04; *a++ = 0x62; *a++ = 0x44;             /*  or t2,t1,t1  */
                        *a++ = 0xc3; *a++ = 0x50; *a++ = 0x20; *a++ = 0x48;             /*  extbl t0,2,t2  */
                        *a++ = 0x23; *a++ = 0x17; *a++ = 0x61; *a++ = 0x48;             /*  sll t2,8,t2  */
                        *a++ = 0x02; *a++ = 0x04; *a++ = 0x62; *a++ = 0x44;             /*  or t2,t1,t1  */
                        *a++ = 0xc3; *a++ = 0x70; *a++ = 0x20; *a++ = 0x48;             /*  extbl t0,3,t2  */
                        *a++ = 0x01; *a++ = 0x04; *a++ = 0x62; *a++ = 0x44;             /*  or t2,t1,t0  */

                        /*  or the results together:  */
                        *a++ = 0x01; *a++ = 0x04; *a++ = 0xa1; *a++ = 0x44;             /*  or t4,t0,t0  */
                }
                bintrans_move_Alpha_reg_into_MIPS_reg(&a, ALPHA_T0, rt);
                break;
        case HI6_LW:
        case HI6_LWU:
                if (alpha_rt < 0 || bigendian || instruction_type == HI6_LWU)
                        alpha_rt = ALPHA_T0;
                /*  ldl rt,0(t3)  */
                *a++ = 0x00; *a++ = 0x00; *a++ = 0x04 | ((alpha_rt & 7) << 5);
                    *a++ = 0xa0 | ((alpha_rt >> 3) & 3);
                if (bigendian) {
                        *a++ = 0x62; *a++ = 0x71; *a++ = 0x20; *a++ = 0x48;             /*  insbl t0,3,t1  */
                        *a++ = 0xc3; *a++ = 0x30; *a++ = 0x20; *a++ = 0x48;             /*  extbl t0,1,t2  */
                        *a++ = 0x23; *a++ = 0x17; *a++ = 0x62; *a++ = 0x48;             /*  sll t2,16,t2  */
                        *a++ = 0x02; *a++ = 0x04; *a++ = 0x62; *a++ = 0x44;             /*  or t2,t1,t1  */
                        *a++ = 0xc3; *a++ = 0x50; *a++ = 0x20; *a++ = 0x48;             /*  extbl t0,2,t2  */
                        *a++ = 0x23; *a++ = 0x17; *a++ = 0x61; *a++ = 0x48;             /*  sll t2,8,t2  */
                        *a++ = 0x02; *a++ = 0x04; *a++ = 0x62; *a++ = 0x44;             /*  or t2,t1,t1  */
                        *a++ = 0xc3; *a++ = 0x70; *a++ = 0x20; *a++ = 0x48;             /*  extbl t0,3,t2  */
                        *a++ = 0x01; *a++ = 0x04; *a++ = 0x62; *a++ = 0x44;             /*  or t2,t1,t0  */
                        *a++ = 0x01; *a++ = 0x00; *a++ = 0x3f; *a++ = 0x40;             /*  addl t0,zero,t0 (sign extend) 32->64  */
                }
                if (instruction_type == HI6_LWU) {
                        /*  Use only lowest 32 bits:  */
                        *a++ = 0x21; *a++ = 0xf6; *a++ = 0x21; *a++ = 0x48;     /*  zapnot t0,0xf,t0  */
                }
                if (alpha_rt == ALPHA_T0)
                        bintrans_move_Alpha_reg_into_MIPS_reg(&a, ALPHA_T0, rt);
                break;
        case HI6_LHU:
        case HI6_LH:
                *a++ = 0x00; *a++ = 0x00; *a++ = 0x24; *a++ = 0x30;                     /*  ldwu from memory  */
                if (bigendian) {
                        *a++ = 0x62; *a++ = 0x31; *a++ = 0x20; *a++ = 0x48;             /*  insbl t0,1,t1  */
                        *a++ = 0xc3; *a++ = 0x30; *a++ = 0x20; *a++ = 0x48;             /*  extbl t0,1,t2  */
                        *a++ = 0x01; *a++ = 0x04; *a++ = 0x43; *a++ = 0x44;             /*  or t1,t2,t0  */
                }
                if (instruction_type == HI6_LH) {
                        *a++ = 0x21; *a++ = 0x00; *a++ = 0xe1; *a++ = 0x73;             /*  sextw   t0,t0  */
                }
                bintrans_move_Alpha_reg_into_MIPS_reg(&a, ALPHA_T0, rt);
                break;
        case HI6_LBU:
        case HI6_LB:
                if (alpha_rt < 0)
                        alpha_rt = ALPHA_T0;
                /*  ldbu rt,0(t3)  */
                *a++ = 0x00; *a++ = 0x00; *a++ = 0x04 | ((alpha_rt & 7) << 5);
                    *a++ = 0x28 | ((alpha_rt >> 3) & 3);
                if (instruction_type == HI6_LB) {
                        /*  sextb rt,rt  */
                        *a++ = alpha_rt; *a++ = 0x00; *a++ = 0xe0 + alpha_rt; *a++ = 0x73;
                }
                if (alpha_rt == ALPHA_T0)
                        bintrans_move_Alpha_reg_into_MIPS_reg(&a, ALPHA_T0, rt);
                break;

        case HI6_LWL:
                /*  a1 = 0..3 (or 0..7 for 64-bit loads):  */
                alpha_rs = map_MIPS_to_Alpha[rs];
                if (alpha_rs < 0) {
                        bintrans_move_MIPS_reg_into_Alpha_reg(&a, rs, ALPHA_T0);
                        alpha_rs = ALPHA_T0;
                }
                *a++ = imm; *a++ = (imm >> 8); *a++ = 0x20 + alpha_rs; *a++ = 0x22;
                /*  02 30 20 46     and     a1,alignment,t1  */
                *a++ = 0x02; *a++ = 0x10 + alignment * 0x20; *a++ = 0x20 + (alignment >> 3); *a++ = 0x46;

                /*  ldl t0,0(t3)  */
                *a++ = 0x00; *a++ = 0x00; *a++ = 0x24; *a++ = 0xa0;

                if (bigendian) {
                        /*  TODO  */
                        bintrans_write_chunkreturn_fail(&a);
                }
                /*
                 *  lwl:  memory = 0x12 0x34 0x56 0x78
                 *      offset (a1):    register rt becomes:
                 *      0               0x12......
                 *      1               0x3412....
                 *      2               0x563412..
                 *      3               0x78563412
                 */

                bintrans_move_MIPS_reg_into_Alpha_reg(&a, rt, ALPHA_T2);

/*
  10:   03 00 9f 20     lda     t3,3
  14:   a5 05 82 40     cmpeq   t3,t1,t4
  18:   01 00 a0 e4     beq     t4,20 <skip>
*/
*a++ = 0x03; *a++ = 0x00; *a++ = 0x9f; *a++ = 0x20;
*a++ = 0xa5; *a++ = 0x05; *a++ = 0x82; *a++ = 0x40;
*a++ = 0x02; *a++ = 0x00; *a++ = 0xa0; *a++ = 0xe4;

/* 03 14 20 40     addq    t0,0,t2  */
*a++ = 0x03; *a++ = 0x14; *a++ = 0x20; *a++ = 0x40;

ok_unaligned_load3 = a;
*a++ = 0x01; *a++ = 0x00; *a++ = 0xe0; *a++ = 0xc3;


*a++ = 0x02; *a++ = 0x00; *a++ = 0x9f; *a++ = 0x20;
*a++ = 0xa5; *a++ = 0x05; *a++ = 0x82; *a++ = 0x40;
*a++ = 0x05; *a++ = 0x00; *a++ = 0xa0; *a++ = 0xe4;
/*
                 *      2               0x563412..
  2c:   21 17 21 48     sll     t0,0x8,t0
  30:   01 10 20 40     addl    t0,0,t0
  34:   03 f0 7f 44     and     t2,0xff,t2
  38:   03 04 23 44     or      t0,t2,t2
*/
*a++ = 0x21; *a++ = 0x17; *a++ = 0x21; *a++ = 0x48;
*a++ = 0x01; *a++ = 0x10; *a++ = 0x20; *a++ = 0x40;
*a++ = 0x03; *a++ = 0xf0; *a++ = 0x7f; *a++ = 0x44;
*a++ = 0x03; *a++ = 0x04; *a++ = 0x23; *a++ = 0x44;

ok_unaligned_load2 = a;
*a++ = 0x01; *a++ = 0x00; *a++ = 0xe0; *a++ = 0xc3;


*a++ = 0x01; *a++ = 0x00; *a++ = 0x9f; *a++ = 0x20;
*a++ = 0xa5; *a++ = 0x05; *a++ = 0x82; *a++ = 0x40;
*a++ = 0x05; *a++ = 0x00; *a++ = 0xa0; *a++ = 0xe4;
/*
                 *      1               0x3412....
  2c:   21 17 22 48     sll     t0,0x10,t0
  30:   01 10 20 40     addl    t0,0,t0
  34:   23 76 60 48     zapnot  t2,0x3,t2
  38:   03 04 23 44     or      t0,t2,t2
*/
*a++ = 0x21; *a++ = 0x17; *a++ = 0x22; *a++ = 0x48;
*a++ = 0x01; *a++ = 0x10; *a++ = 0x20; *a++ = 0x40;
*a++ = 0x23; *a++ = 0x76; *a++ = 0x60; *a++ = 0x48;
*a++ = 0x03; *a++ = 0x04; *a++ = 0x23; *a++ = 0x44;

ok_unaligned_load1 = a;
*a++ = 0x01; *a++ = 0x00; *a++ = 0xe0; *a++ = 0xc3;


/*
                 *      0               0x12......
  2c:   21 17 23 48     sll     t0,0x18,t0
  30:   01 10 20 40     addl    t0,0,t0
  34:   23 f6 60 48     zapnot  t2,0x7,t2
  38:   03 04 23 44     or      t0,t2,t2
*/
*a++ = 0x21; *a++ = 0x17; *a++ = 0x23; *a++ = 0x48;
*a++ = 0x01; *a++ = 0x10; *a++ = 0x20; *a++ = 0x40;
*a++ = 0x23; *a++ = 0xf6; *a++ = 0x60; *a++ = 0x48;
*a++ = 0x03; *a++ = 0x04; *a++ = 0x23; *a++ = 0x44;


                *ok_unaligned_load3 = ((size_t)a - (size_t)ok_unaligned_load3 - 4) / 4;
                *ok_unaligned_load2 = ((size_t)a - (size_t)ok_unaligned_load2 - 4) / 4;
                *ok_unaligned_load1 = ((size_t)a - (size_t)ok_unaligned_load1 - 4) / 4;

/*  03 10 60 40     addl    t2,0,t2  */
*a++ = 0x03; *a++ = 0x10; *a++ = 0x60; *a++ = 0x40;

                bintrans_move_Alpha_reg_into_MIPS_reg(&a, ALPHA_T2, rt);
                break;

        case HI6_LWR:
                /*  a1 = 0..3 (or 0..7 for 64-bit loads):  */
                alpha_rs = map_MIPS_to_Alpha[rs];
                if (alpha_rs < 0) {
                        bintrans_move_MIPS_reg_into_Alpha_reg(&a, rs, ALPHA_T0);
                        alpha_rs = ALPHA_T0;
                }
                *a++ = imm; *a++ = (imm >> 8); *a++ = 0x20 + alpha_rs; *a++ = 0x22;
                /*  02 30 20 46     and     a1,alignment,t1  */
                *a++ = 0x02; *a++ = 0x10 + alignment * 0x20; *a++ = 0x20 + (alignment >> 3); *a++ = 0x46;

                /*  ldl t0,0(t3)  */
                *a++ = 0x00; *a++ = 0x00; *a++ = 0x24; *a++ = 0xa0;

                if (bigendian) {
                        /*  TODO  */
                        bintrans_write_chunkreturn_fail(&a);
                }
                /*
                 *  lwr:  memory = 0x12 0x34 0x56 0x78
                 *      offset (a1):    register rt becomes:
                 *      0               0x78563412
                 *      1               0x..785634
                 *      2               0x....7856
                 *      3               0x......78
                 */

                bintrans_move_MIPS_reg_into_Alpha_reg(&a, rt, ALPHA_T2);

/*
  10:   03 00 9f 20     lda     t3,3
  14:   a5 05 82 40     cmpeq   t3,t1,t4
  18:   01 00 a0 e4     beq     t4,20 <skip>
*/
*a++ = 0x03; *a++ = 0x00; *a++ = 0x9f; *a++ = 0x20;
*a++ = 0xa5; *a++ = 0x05; *a++ = 0x82; *a++ = 0x40;
*a++ = 0x05; *a++ = 0x00; *a++ = 0xa0; *a++ = 0xe4;

/*
  2c:   81 16 23 48     srl     t0,0x18,t0
  b0:   21 36 20 48     zapnot  t0,0x1,t0
  34:   23 d6 7f 48     zapnot  t2,0xfe,t2
  38:   03 04 23 44     or      t0,t2,t2
*/
*a++ = 0x81; *a++ = 0x16; *a++ = 0x23; *a++ = 0x48;
*a++ = 0x21; *a++ = 0x36; *a++ = 0x20; *a++ = 0x48;
*a++ = 0x23; *a++ = 0xd6; *a++ = 0x7f; *a++ = 0x48;
*a++ = 0x03; *a++ = 0x04; *a++ = 0x23; *a++ = 0x44;

ok_unaligned_load3 = a;
*a++ = 0x01; *a++ = 0x00; *a++ = 0xe0; *a++ = 0xc3;


*a++ = 0x02; *a++ = 0x00; *a++ = 0x9f; *a++ = 0x20;
*a++ = 0xa5; *a++ = 0x05; *a++ = 0x82; *a++ = 0x40;
*a++ = 0x05; *a++ = 0x00; *a++ = 0xa0; *a++ = 0xe4;
/*
  2c:   81 16 22 48     srl     t0,0x10,t0
  b4:   21 76 20 48     zapnot  t0,0x3,t0
  34:   23 96 7f 48     zapnot  t2,0xfc,t2
  38:   03 04 23 44     or      t0,t2,t2
*/
*a++ = 0x81; *a++ = 0x16; *a++ = 0x22; *a++ = 0x48;
*a++ = 0x21; *a++ = 0x76; *a++ = 0x20; *a++ = 0x48;
*a++ = 0x23; *a++ = 0x96; *a++ = 0x7f; *a++ = 0x48;
*a++ = 0x03; *a++ = 0x04; *a++ = 0x23; *a++ = 0x44;

ok_unaligned_load2 = a;
*a++ = 0x01; *a++ = 0x00; *a++ = 0xe0; *a++ = 0xc3;


*a++ = 0x01; *a++ = 0x00; *a++ = 0x9f; *a++ = 0x20;
*a++ = 0xa5; *a++ = 0x05; *a++ = 0x82; *a++ = 0x40;
*a++ = 0x05; *a++ = 0x00; *a++ = 0xa0; *a++ = 0xe4;
/*
  2c:   81 16 21 48     srl     t0,0x8,t0
  b8:   21 f6 20 48     zapnot  t0,0x7,t0
  3c:   23 16 7f 48     zapnot  t2,0xf8,t2
  40:   03 04 23 44     or      t0,t2,t2
*/
*a++ = 0x81; *a++ = 0x16; *a++ = 0x21; *a++ = 0x48;
*a++ = 0x21; *a++ = 0xf6; *a++ = 0x20; *a++ = 0x48;
*a++ = 0x23; *a++ = 0x16; *a++ = 0x7f; *a++ = 0x48;
*a++ = 0x03; *a++ = 0x04; *a++ = 0x23; *a++ = 0x44;

ok_unaligned_load1 = a;
*a++ = 0x01; *a++ = 0x00; *a++ = 0xe0; *a++ = 0xc3;


/*
                 *      0               0x12......
*/
/* 03 14 20 40     addq    t0,0,t2  */
*a++ = 0x03; *a++ = 0x14; *a++ = 0x20; *a++ = 0x40;


                *ok_unaligned_load3 = ((size_t)a - (size_t)ok_unaligned_load3 - 4) / 4;
                *ok_unaligned_load2 = ((size_t)a - (size_t)ok_unaligned_load2 - 4) / 4;
                *ok_unaligned_load1 = ((size_t)a - (size_t)ok_unaligned_load1 - 4) / 4;

/*  03 10 60 40     addl    t2,0,t2  */
*a++ = 0x03; *a++ = 0x10; *a++ = 0x60; *a++ = 0x40;

                bintrans_move_Alpha_reg_into_MIPS_reg(&a, ALPHA_T2, rt);
                break;

        case HI6_SQ:
                /*  TODO  */
                break;
        case HI6_SD:
                bintrans_move_MIPS_reg_into_Alpha_reg(&a, rt, ALPHA_T0);
                if (bigendian) {
                        /*  remember original 8 bytes of t0:  */
                        *a++ = 0x05; *a++ = 0x04; *a++ = 0x3f; *a++ = 0x40;             /*  addq t0,zero,t4  */

                        /*  swap lowest 4 bytes:  */
                        *a++ = 0x62; *a++ = 0x71; *a++ = 0x20; *a++ = 0x48;             /*  insbl t0,3,t1  */
                        *a++ = 0xc3; *a++ = 0x30; *a++ = 0x20; *a++ = 0x48;             /*  extbl t0,1,t2  */
                        *a++ = 0x23; *a++ = 0x17; *a++ = 0x62; *a++ = 0x48;             /*  sll t2,16,t2  */
                        *a++ = 0x02; *a++ = 0x04; *a++ = 0x62; *a++ = 0x44;             /*  or t2,t1,t1  */
                        *a++ = 0xc3; *a++ = 0x50; *a++ = 0x20; *a++ = 0x48;             /*  extbl t0,2,t2  */
                        *a++ = 0x23; *a++ = 0x17; *a++ = 0x61; *a++ = 0x48;             /*  sll t2,8,t2  */
                        *a++ = 0x02; *a++ = 0x04; *a++ = 0x62; *a++ = 0x44;             /*  or t2,t1,t1  */
                        *a++ = 0xc3; *a++ = 0x70; *a++ = 0x20; *a++ = 0x48;             /*  extbl t0,3,t2  */
                        *a++ = 0x01; *a++ = 0x04; *a++ = 0x62; *a++ = 0x44;             /*  or t2,t1,t0  */

                        /*  save result in (top 4 bytes of) t1, then t4. get back top bits of t4:  */
                        *a++ = 0x22; *a++ = 0x17; *a++ = 0x24; *a++ = 0x48;             /*  sll t0,0x20,t1  */
                        *a++ = 0x81; *a++ = 0x16; *a++ = 0xa4; *a++ = 0x48;             /*  srl t4,0x20,t0  */
                        *a++ = 0x05; *a++ = 0x14; *a++ = 0x40; *a++ = 0x40;             /*  addq t1,0,t4  */

                        /*  swap highest 4 bytes:  */
                        *a++ = 0x62; *a++ = 0x71; *a++ = 0x20; *a++ = 0x48;             /*  insbl t0,3,t1  */
                        *a++ = 0xc3; *a++ = 0x30; *a++ = 0x20; *a++ = 0x48;             /*  extbl t0,1,t2  */
                        *a++ = 0x23; *a++ = 0x17; *a++ = 0x62; *a++ = 0x48;             /*  sll t2,16,t2  */
                        *a++ = 0x02; *a++ = 0x04; *a++ = 0x62; *a++ = 0x44;             /*  or t2,t1,t1  */
                        *a++ = 0xc3; *a++ = 0x50; *a++ = 0x20; *a++ = 0x48;             /*  extbl t0,2,t2  */
                        *a++ = 0x23; *a++ = 0x17; *a++ = 0x61; *a++ = 0x48;             /*  sll t2,8,t2  */
                        *a++ = 0x02; *a++ = 0x04; *a++ = 0x62; *a++ = 0x44;             /*  or t2,t1,t1  */
                        *a++ = 0xc3; *a++ = 0x70; *a++ = 0x20; *a++ = 0x48;             /*  extbl t0,3,t2  */
                        *a++ = 0x01; *a++ = 0x04; *a++ = 0x62; *a++ = 0x44;             /*  or t2,t1,t0  */

                        /*  or the results together:  */
                        *a++ = 0x01; *a++ = 0x04; *a++ = 0xa1; *a++ = 0x44;             /*  or t4,t0,t0  */
                }
                *a++ = 0x00; *a++ = 0x00; *a++ = 0x24; *a++ = 0xb4;                     /*  stq to memory  */
                break;
        case HI6_SW:
                if (alpha_rt < 0 || bigendian) {
                        bintrans_move_MIPS_reg_into_Alpha_reg(&a, rt, ALPHA_T0);
                        alpha_rt = ALPHA_T0;
                }
                if (bigendian) {
                        *a++ = 0x62; *a++ = 0x71; *a++ = 0x20; *a++ = 0x48;             /*  insbl t0,3,t1  */
                        *a++ = 0xc3; *a++ = 0x30; *a++ = 0x20; *a++ = 0x48;             /*  extbl t0,1,t2  */
                        *a++ = 0x23; *a++ = 0x17; *a++ = 0x62; *a++ = 0x48;             /*  sll t2,16,t2  */
                        *a++ = 0x02; *a++ = 0x04; *a++ = 0x62; *a++ = 0x44;             /*  or t2,t1,t1  */
                        *a++ = 0xc3; *a++ = 0x50; *a++ = 0x20; *a++ = 0x48;             /*  extbl t0,2,t2  */
                        *a++ = 0x23; *a++ = 0x17; *a++ = 0x61; *a++ = 0x48;             /*  sll t2,8,t2  */
                        *a++ = 0x02; *a++ = 0x04; *a++ = 0x62; *a++ = 0x44;             /*  or t2,t1,t1  */
                        *a++ = 0xc3; *a++ = 0x70; *a++ = 0x20; *a++ = 0x48;             /*  extbl t0,3,t2  */
                        *a++ = 0x01; *a++ = 0x04; *a++ = 0x62; *a++ = 0x44;             /*  or t2,t1,t0  */
                }
                /*  stl to memory:  stl rt,0(t3)  */
                *a++ = 0x00; *a++ = 0x00; *a++ = 0x04 | ((alpha_rt & 7) << 5);
                    *a++ = 0xb0 | ((alpha_rt >> 3) & 3);
                break;
        case HI6_SH:
                bintrans_move_MIPS_reg_into_Alpha_reg(&a, rt, ALPHA_T0);
                if (bigendian) {
                        *a++ = 0x62; *a++ = 0x31; *a++ = 0x20; *a++ = 0x48;             /*  insbl t0,1,t1  */
                        *a++ = 0xc3; *a++ = 0x30; *a++ = 0x20; *a++ = 0x48;             /*  extbl t0,1,t2  */
                        *a++ = 0x01; *a++ = 0x04; *a++ = 0x43; *a++ = 0x44;             /*  or t1,t2,t0  */
                }
                *a++ = 0x00; *a++ = 0x00; *a++ = 0x24; *a++ = 0x34;                     /*  stw to memory  */
                break;
        case HI6_SB:
                if (alpha_rt < 0) {
                        bintrans_move_MIPS_reg_into_Alpha_reg(&a, rt, ALPHA_T0);
                        alpha_rt = ALPHA_T0;
                }
                /*  stb to memory:  stb rt,0(t3)  */
                *a++ = 0x00; *a++ = 0x00; *a++ = 0x04 | ((alpha_rt & 7) << 5);
                    *a++ = 0x38 | ((alpha_rt >> 3) & 3);
                break;

        case HI6_SWL:
                /*  a1 = 0..3 (or 0..7 for 64-bit stores):  */
                alpha_rs = map_MIPS_to_Alpha[rs];
                if (alpha_rs < 0) {
                        bintrans_move_MIPS_reg_into_Alpha_reg(&a, rs, ALPHA_T0);
                        alpha_rs = ALPHA_T0;
                }
                *a++ = imm; *a++ = (imm >> 8); *a++ = 0x20 + alpha_rs; *a++ = 0x22;
                /*  02 30 20 46     and     a1,alignment,t1  */
                *a++ = 0x02; *a++ = 0x10 + alignment * 0x20; *a++ = 0x20 + (alignment >> 3); *a++ = 0x46;

                /*  ldl t0,0(t3)  */
                *a++ = 0x00; *a++ = 0x00; *a++ = 0x24; *a++ = 0xa0;

                if (bigendian) {
                        /*  TODO  */
                        bintrans_write_chunkreturn_fail(&a);
                }

                bintrans_move_MIPS_reg_into_Alpha_reg(&a, rt, ALPHA_T2);

                /*
                 *  swl:        memory = 0x12 0x34 0x56 0x78
                 *              register = 0x89abcdef
                 *      offset (a1):    memory becomes:
                 *      0               0x89 0x.. 0x.. 0x..
                 *      1               0xab 0x89 0x.. 0x..
                 *      2               0xcd 0xab 0x89 0x..
                 *      3               0xef 0xcd 0xab 0x89
                 */

/*
  a5 75 40 40     cmpeq   t1,0x03,t4
  01 00 a0 e4     beq     t4,20 <skip>
*/
*a++ = 0xa5; *a++ = 0x75; *a++ = 0x40; *a++ = 0x40;
*a++ = 0x02; *a++ = 0x00; *a++ = 0xa0; *a++ = 0xe4;

/*  01 10 60 40     addl    t2,0,t0  */
*a++ = 0x01; *a++ = 0x10; *a++ = 0x60; *a++ = 0x40;

ok_unaligned_load3 = a;
*a++ = 0x01; *a++ = 0x00; *a++ = 0xe0; *a++ = 0xc3;


*a++ = 0xa5; *a++ = 0x55; *a++ = 0x40; *a++ = 0x40;
*a++ = 0x05; *a++ = 0x00; *a++ = 0xa0; *a++ = 0xe4;
/*
  2:
  e8:   83 16 61 48     srl     t2,0x8,t2
  ec:   23 f6 60 48     zapnot  t2,0x7,t2
  f0:   21 16 3f 48     zapnot  t0,0xf8,t0
  f4:   01 04 23 44     or      t0,t2,t0
*/
*a++ = 0x83; *a++ = 0x16; *a++ = 0x61; *a++ = 0x48;
*a++ = 0x23; *a++ = 0xf6; *a++ = 0x60; *a++ = 0x48;
*a++ = 0x21; *a++ = 0x16; *a++ = 0x3f; *a++ = 0x48;
*a++ = 0x01; *a++ = 0x04; *a++ = 0x23; *a++ = 0x44;

ok_unaligned_load2 = a;
*a++ = 0x01; *a++ = 0x00; *a++ = 0xe0; *a++ = 0xc3;


*a++ = 0xa5; *a++ = 0x35; *a++ = 0x40; *a++ = 0x40;
*a++ = 0x05; *a++ = 0x00; *a++ = 0xa0; *a++ = 0xe4;
/*
  1:
  f8:   83 16 62 48     srl     t2,0x10,t2
  fc:   23 76 60 48     zapnot  t2,0x3,t2
 100:   21 96 3f 48     zapnot  t0,0xfc,t0
 104:   01 04 23 44     or      t0,t2,t0
*/
*a++ = 0x83; *a++ = 0x16; *a++ = 0x62; *a++ = 0x48;
*a++ = 0x23; *a++ = 0x76; *a++ = 0x60; *a++ = 0x48;
*a++ = 0x21; *a++ = 0x96; *a++ = 0x3f; *a++ = 0x48;
*a++ = 0x01; *a++ = 0x04; *a++ = 0x23; *a++ = 0x44;

ok_unaligned_load1 = a;
*a++ = 0x01; *a++ = 0x00; *a++ = 0xe0; *a++ = 0xc3;


/*
 0:
 108:   83 16 63 48     srl     t2,0x18,t2
 10c:   23 36 60 48     zapnot  t2,0x1,t2
 110:   21 d6 3f 48     zapnot  t0,0xfe,t0
 114:   01 04 23 44     or      t0,t2,t0
*/
*a++ = 0x83; *a++ = 0x16; *a++ = 0x63; *a++ = 0x48;
*a++ = 0x23; *a++ = 0x36; *a++ = 0x60; *a++ = 0x48;
*a++ = 0x21; *a++ = 0xd6; *a++ = 0x3f; *a++ = 0x48;
*a++ = 0x01; *a++ = 0x04; *a++ = 0x23; *a++ = 0x44;


                *ok_unaligned_load3 = ((size_t)a - (size_t)ok_unaligned_load3 - 4) / 4;
                *ok_unaligned_load2 = ((size_t)a - (size_t)ok_unaligned_load2 - 4) / 4;
                *ok_unaligned_load1 = ((size_t)a - (size_t)ok_unaligned_load1 - 4) / 4;

                /*  sdl t0,0(t3)  */
                *a++ = 0x00; *a++ = 0x00; *a++ = 0x24; *a++ = 0xb0;
                break;

        case HI6_SWR:
                /*  a1 = 0..3 (or 0..7 for 64-bit stores):  */
                alpha_rs = map_MIPS_to_Alpha[rs];
                if (alpha_rs < 0) {
                        bintrans_move_MIPS_reg_into_Alpha_reg(&a, rs, ALPHA_T0);
                        alpha_rs = ALPHA_T0;
                }
                *a++ = imm; *a++ = (imm >> 8); *a++ = 0x20 + alpha_rs; *a++ = 0x22;
                /*  02 30 20 46     and     a1,alignment,t1  */
                *a++ = 0x02; *a++ = 0x10 + alignment * 0x20; *a++ = 0x20 + (alignment >> 3); *a++ = 0x46;

                /*  ldl t0,0(t3)  */
                *a++ = 0x00; *a++ = 0x00; *a++ = 0x24; *a++ = 0xa0;

                if (bigendian) {
                        /*  TODO  */
                        bintrans_write_chunkreturn_fail(&a);
                }

                bintrans_move_MIPS_reg_into_Alpha_reg(&a, rt, ALPHA_T2);

                /*
                 *  swr:        memory = 0x12 0x34 0x56 0x78
                 *              register = 0x89abcdef
                 *      offset (a1):    memory becomes:
                 *      0               0xef 0xcd 0xab 0x89
                 *      1               0x.. 0xef 0xcd 0xab
                 *      2               0x.. 0x.. 0xef 0xcd
                 *      3               0x.. 0x.. 0x.. 0xef
                 */


/*
  a5 75 40 40     cmpeq   t1,0x03,t4
  01 00 a0 e4     beq     t4,20 <skip>
*/
*a++ = 0xa5; *a++ = 0x75; *a++ = 0x40; *a++ = 0x40;
*a++ = 0x04; *a++ = 0x00; *a++ = 0xa0; *a++ = 0xe4;

/*
 118:   23 17 63 48     sll     t2,0x18,t2
 11c:   21 f6 20 48     zapnot  t0,0x7,t0
 120:   01 04 23 44     or      t0,t2,t0
*/
*a++ = 0x23; *a++ = 0x17; *a++ = 0x63; *a++ = 0x48;
*a++ = 0x21; *a++ = 0xf6; *a++ = 0x20; *a++ = 0x48;
*a++ = 0x01; *a++ = 0x04; *a++ = 0x23; *a++ = 0x44;

ok_unaligned_load3 = a;
*a++ = 0x01; *a++ = 0x00; *a++ = 0xe0; *a++ = 0xc3;


*a++ = 0xa5; *a++ = 0x55; *a++ = 0x40; *a++ = 0x40;
*a++ = 0x04; *a++ = 0x00; *a++ = 0xa0; *a++ = 0xe4;
/*
  2:
 124:   23 17 62 48     sll     t2,0x10,t2
 128:   21 76 20 48     zapnot  t0,0x3,t0
 12c:   01 04 23 44     or      t0,t2,t0
*/
*a++ = 0x23; *a++ = 0x17; *a++ = 0x62; *a++ = 0x48;
*a++ = 0x21; *a++ = 0x76; *a++ = 0x20; *a++ = 0x48;
*a++ = 0x01; *a++ = 0x04; *a++ = 0x23; *a++ = 0x44;

ok_unaligned_load2 = a;
*a++ = 0x01; *a++ = 0x00; *a++ = 0xe0; *a++ = 0xc3;


*a++ = 0xa5; *a++ = 0x35; *a++ = 0x40; *a++ = 0x40;
*a++ = 0x04; *a++ = 0x00; *a++ = 0xa0; *a++ = 0xe4;
/*
  1:
 130:   23 17 61 48     sll     t2,0x8,t2
 134:   21 36 20 48     zapnot  t0,0x1,t0
 138:   01 04 23 44     or      t0,t2,t0
*/
*a++ = 0x23; *a++ = 0x17; *a++ = 0x61; *a++ = 0x48;
*a++ = 0x21; *a++ = 0x36; *a++ = 0x20; *a++ = 0x48;
*a++ = 0x01; *a++ = 0x04; *a++ = 0x23; *a++ = 0x44;

ok_unaligned_load1 = a;
*a++ = 0x01; *a++ = 0x00; *a++ = 0xe0; *a++ = 0xc3;


/*
 0:
 13c:   01 10 60 40     addl    t2,0,t0
*/
*a++ = 0x01; *a++ = 0x10; *a++ = 0x60; *a++ = 0x40;


                *ok_unaligned_load3 = ((size_t)a - (size_t)ok_unaligned_load3 - 4) / 4;
                *ok_unaligned_load2 = ((size_t)a - (size_t)ok_unaligned_load2 - 4) / 4;
                *ok_unaligned_load1 = ((size_t)a - (size_t)ok_unaligned_load1 - 4) / 4;

                /*  sdl t0,0(t3)  */
                *a++ = 0x00; *a++ = 0x00; *a++ = 0x24; *a++ = 0xb0;
                break;

        default:
                ;
        }

        *addrp = a;
        bintrans_write_pc_inc(addrp);
        return 1;
}


/*
 *  bintrans_write_instruction__lui():
 */
static int bintrans_write_instruction__lui(unsigned char **addrp,
        int rt, int imm)
{
        uint32_t *a;

        /*
         *  dc fe 3f 24     ldah    t0,-292
         *  1f 04 ff 5f     fnop
         *  88 08 30 b4     stq     t0,2184(a0)
         */
        if (rt != 0) {
                int alpha_rt = map_MIPS_to_Alpha[rt];
                if (alpha_rt < 0)
                        alpha_rt = ALPHA_T0;

                a = (uint32_t *) *addrp;
                *a++ = 0x241f0000 | (alpha_rt << 21) | ((uint32_t)imm & 0xffff);
                *addrp = (unsigned char *) a;

                if (alpha_rt == ALPHA_T0) {
                        *a++ = 0x5fff041f;      /*  fnop  */
                        bintrans_move_Alpha_reg_into_MIPS_reg(addrp, ALPHA_T0, rt);
                }
        }

        bintrans_write_pc_inc(addrp);

        return 1;
}


/*
 *  bintrans_write_instruction__mfmthilo():
 */
static int bintrans_write_instruction__mfmthilo(unsigned char **addrp,
        int rd, int from_flag, int hi_flag)
{
        unsigned char *a;
        int ofs;

        a = *addrp;

        /*
         *   18 09 30 a4     ldq     t0,hi(a0)  (or lo)
         *   18 09 30 b4     stq     t0,rd(a0)
         *
         *   (or if from_flag is cleared then move the other way, it's
         *   actually not rd then, but rs...)
         */

        if (from_flag) {
                if (rd != 0) {
                        /*  mfhi or mflo  */
                        if (hi_flag)
                                ofs = ((size_t)&dummy_cpu.cd.mips.hi) - (size_t)&dummy_cpu;
                        else
                                ofs = ((size_t)&dummy_cpu.cd.mips.lo) - (size_t)&dummy_cpu;
                        *a++ = (ofs & 255); *a++ = (ofs >> 8); *a++ = 0x30; *a++ = 0xa4;

                        bintrans_move_Alpha_reg_into_MIPS_reg(&a, ALPHA_T0, rd);
                }
        } else {
                /*  mthi or mtlo  */
                bintrans_move_MIPS_reg_into_Alpha_reg(&a, rd, ALPHA_T0);

                if (hi_flag)
                        ofs = ((size_t)&dummy_cpu.cd.mips.hi) - (size_t)&dummy_cpu;
                else
                        ofs = ((size_t)&dummy_cpu.cd.mips.lo) - (size_t)&dummy_cpu;
                *a++ = (ofs & 255); *a++ = (ofs >> 8); *a++ = 0x30; *a++ = 0xb4;
        }

        *addrp = a;
        bintrans_write_pc_inc(addrp);
        return 1;
}


/*
 *  bintrans_write_instruction__mfc_mtc():
 */
static int bintrans_write_instruction__mfc_mtc(struct memory *mem,
        unsigned char **addrp, int coproc_nr, int flag64bit, int rt,
        int rd, int mtcflag)
{
        uint32_t *a, *jump;
        int ofs;

        /*
         *  NOTE: Only a few registers are readable without side effects.
         */
        if (rt == 0 && !mtcflag)
                return 0;

        if (coproc_nr >= 1)
                return 0;

        if (rd == COP0_RANDOM || rd == COP0_COUNT)
                return 0;


        /*************************************************************
         *
         *  TODO: Check for kernel mode, or Coproc X usability bit!
         *
         *************************************************************/

        a = (uint32_t *) *addrp;

        ofs = ((size_t)&dummy_cpu.cd.mips.coproc[0]) - (size_t)&dummy_cpu;
        *a++ = 0xa4300000 | (ofs & 0xffff);             /*  ldq t0,coproc[0](a0)  */

        ofs = ((size_t)&dummy_coproc.reg[rd]) - (size_t)&dummy_coproc;
        *a++ = 0xa4410000 | (ofs & 0xffff);             /*  ldq t1,reg_rd(t0)  */

        if (mtcflag) {
                /*  mtc:  */
                *addrp = (unsigned char *) a;
                bintrans_move_MIPS_reg_into_Alpha_reg(addrp, rt, ALPHA_T0);
                a = (uint32_t *) *addrp;

                if (!flag64bit) {
                        *a++ = 0x40201001;      /*  addl t0,0,t0  */
                        *a++ = 0x40401002;      /*  addl t1,0,t1  */
                }

                /*
                 *  In the general case:  Only allow mtc if it does NOT
                 *  change the register!!
                 */

                switch (rd) {
                case COP0_INDEX:
                        break;

                case COP0_EPC:
                        break;

                /*  TODO: Some bits are not writable  */
                case COP0_ENTRYLO0:
                case COP0_ENTRYLO1:
                        break;

                case COP0_ENTRYHI:
                        /*
                         *  Entryhi is ok to write to, as long as the
                         *  ASID isn't changed. (That would require
                         *  cache invalidations etc. Instead of checking
                         *  for MMU3K vs others, we just assume that all the
                         *  lowest 12 bits must be the same.
                         */
                        /*  ff 0f bf 20     lda     t4,0x0fff  */
                        /*  03 00 25 44     and     t0,t4,t2  */
                        /*  04 00 45 44     and     t1,t4,t3  */
                        /*  a3 05 64 40     cmpeq   t2,t3,t2  */
                        /*  01 00 60 f4     bne     t2,<ok>  */
                        *a++ = 0x20bf0fff;
                        *a++ = 0x44250003;
                        *a++ = 0x44450004;
                        *a++ = 0x406405a3;
                        jump = a;
                        *a++ = 0;       /*  later  */
                        *addrp = (unsigned char *) a;
                        bintrans_write_chunkreturn_fail(addrp);
                        a = (uint32_t *) *addrp;
                        *jump = 0xf4600000 | (((size_t)a - (size_t)jump - 4) / 4);
                        break;

                case COP0_STATUS:
                        /*  Only allow updates to the status register if
                            the interrupt enable bits were changed, but no
                            other bits!  */
                        if (mem->bintrans_32bit_only) {
                                /*  R3000 etc.  */
                                /*  t4 = 0x0fe70000;  */
                                *a++ = 0x20bf0000;
                                *a++ = 0x24a50fe7;
                        } else {
                                /*  fe 00 bf 20     lda     t4,0x00fe  */
                                /*  ff ff a5 24     ldah    t4,-1(t4)  */
                                *a++ = 0x20bf0000;
                                *a++ = 0x24a5ffff;
                        }

                        /*  03 00 25 44     and     t0,t4,t2  */
                        /*  04 00 45 44     and     t1,t4,t3  */
                        /*  a3 05 64 40     cmpeq   t2,t3,t2  */
                        /*  01 00 60 f4     bne     t2,<ok>  */
                        *a++ = 0x44250003;
                        *a++ = 0x44450004;
                        *a++ = 0x406405a3;
                        jump = a;
                        *a++ = 0;       /*  later  */
                        *addrp = (unsigned char *) a;
                        bintrans_write_chunkreturn_fail(addrp);
                        a = (uint32_t *) *addrp;
                        *jump = 0xf4600000 | (((size_t)a - (size_t)jump - 4) / 4);

                        /*  If enabling interrupt bits would cause an
                            exception, then don't do it:  */
                        ofs = ((size_t)&dummy_cpu.cd.mips.coproc[0]) - (size_t)&dummy_cpu;
                        *a++ = 0xa4900000 | (ofs & 0xffff);             /*  ldq t3,coproc[0](a0)  */
                        ofs = ((size_t)&dummy_coproc.reg[COP0_CAUSE]) - (size_t)&dummy_coproc;
                        *a++ = 0xa4a40000 | (ofs & 0xffff);             /*  ldq t4,reg_rd(t3)  */

                        /*  02 00 a1 44     and     t4,t0,t1  */
                        /*  83 16 41 48     srl     t1,0x8,t2  */
                        /*  04 f0 7f 44     and     t2,0xff,t3  */
                        *a++ = 0x44a10002;
                        *a++ = 0x48411683;
                        *a++ = 0x447ff004;
                        /*  01 00 80 e4     beq     t3,<ok>  */
                        jump = a;
                        *a++ = 0;       /*  later  */
                        *addrp = (unsigned char *) a;
                        bintrans_write_chunkreturn_fail(addrp);
                        a = (uint32_t *) *addrp;
                        *jump = 0xe4800000 | (((size_t)a - (size_t)jump - 4) / 4);
                        break;

                default:
                        /*  a3 05 22 40     cmpeq   t0,t1,t2  */
                        /*  01 00 60 f4     bne     t2,<ok>  */
                        *a++ = 0x402205a3;
                        jump = a;
                        *a++ = 0;       /*  later  */
                        *addrp = (unsigned char *) a;
                        bintrans_write_chunkreturn_fail(addrp);
                        a = (uint32_t *) *addrp;
                        *jump = 0xf4600000 | (((size_t)a - (size_t)jump - 4) / 4);
                }

                *a++ = 0x40201402;      /*  addq    t0,0,t1  */

                ofs = ((size_t)&dummy_cpu.cd.mips.coproc[0]) - (size_t)&dummy_cpu;
                *a++ = 0xa4300000 | (ofs & 0xffff);             /*  ldq t0,coproc[0](a0)  */
                ofs = ((size_t)&dummy_coproc.reg[rd]) - (size_t)&dummy_coproc;
                *a++ = 0xb4410000 | (ofs & 0xffff);             /*  stq t1,reg_rd(t0)  */
        } else {
                /*  mfc:  */
                if (!flag64bit) {
                        *a++ = 0x40401002;              /*  addl t1,0,t1  */
                }

                *addrp = (unsigned char *) a;
                bintrans_move_Alpha_reg_into_MIPS_reg(addrp, ALPHA_T1, rt);
                a = (uint32_t *) *addrp;
        }

        *addrp = (unsigned char *) a;

        bintrans_write_pc_inc(addrp);
        return 1;
}


/*
 *  bintrans_write_instruction__tlb_rfe_etc():
 */
static int bintrans_write_instruction__tlb_rfe_etc(unsigned char **addrp,
        int itype)
{
        uint32_t *a;
        int ofs = 0;

        switch (itype) {
        case CALL_TLBWI:
        case CALL_TLBWR:
        case CALL_TLBP:
        case CALL_TLBR:
        case CALL_RFE:
        case CALL_ERET:
        case CALL_BREAK:
        case CALL_SYSCALL:
                break;
        default:
                return 0;
        }

        a = (uint32_t *) *addrp;

        /*  a0 = pointer to the cpu struct  */

        switch (itype) {
        case CALL_TLBWI:
        case CALL_TLBWR:
                /*  a1 = 0 for indexed, 1 for random  */
                *a++ = 0x223f0000 | (itype == CALL_TLBWR);
                break;
        case CALL_TLBP:
        case CALL_TLBR:
                /*  a1 = 0 for probe, 1 for read  */
                *a++ = 0x223f0000 | (itype == CALL_TLBR);
                break;
        case CALL_BREAK:
        case CALL_SYSCALL:
                *a++ = 0x223f0000 | (itype == CALL_BREAK? EXCEPTION_BP : EXCEPTION_SYS);
                break;
        }

        /*  Put PC into the cpu struct (both pc and pc_last).  */
        *a++ = 0xb4d00000 | ofs_pc;     /*  stq t5,"pc"(a0)  */
        *a++ = 0xb4d00000 | ofs_pc_last;/*  stq t5,"pc_last"(a0)  */

        /*  Save a0 and the old return address on the stack:  */
        *a++ = 0x23deff80;              /*  lda sp,-128(sp)  */

        *a++ = 0xb75e0000;              /*  stq ra,0(sp)  */
        *a++ = 0xb61e0008;              /*  stq a0,8(sp)  */
        *a++ = 0xb0fe0018;              /*  stl t6,24(sp)  */
        *a++ = 0xb71e0020;              /*  stq t10,32(sp)  */
        *a++ = 0xb73e0028;              /*  stq t11,40(sp)  */
        *a++ = 0xb51e0030;              /*  stq t7,48(sp)  */
        *a++ = 0xb6de0038;              /*  stq t8,56(sp)  */
        *a++ = 0xb6fe0040;              /*  stq t9,64(sp)  */

        switch (itype) {
        case CALL_TLBP:
        case CALL_TLBR:
                ofs = ((size_t)&dummy_cpu.cd.mips.bintrans_fast_tlbpr) - (size_t)&dummy_cpu;
                break;
        case CALL_TLBWR:
        case CALL_TLBWI:
                ofs = ((size_t)&dummy_cpu.cd.mips.bintrans_fast_tlbwri) - (size_t)&dummy_cpu;
                break;
        case CALL_RFE:
                ofs = ((size_t)&dummy_cpu.cd.mips.bintrans_fast_rfe) - (size_t)&dummy_cpu;
                break;
        case CALL_ERET:
                ofs = ((size_t)&dummy_cpu.cd.mips.bintrans_fast_eret) - (size_t)&dummy_cpu;
                break;
        case CALL_BREAK:
        case CALL_SYSCALL:
                ofs = ((size_t)&dummy_cpu.cd.mips.bintrans_simple_exception) - (size_t)&dummy_cpu;
                break;
        }

        *a++ = 0xa7700000 | ofs;        /*  ldq t12,0(a0)  */

        /*  Call bintrans_fast_tlbwr:  */
        *a++ = 0x6b5b4000;              /*  jsr ra,(t12),<after>  */

        /*  Restore the old return address and a0 from the stack:  */
        *a++ = 0xa75e0000;              /*  ldq ra,0(sp)  */
        *a++ = 0xa61e0008;              /*  ldq a0,8(sp)  */
        *a++ = 0xa0fe0018;              /*  ldl t6,24(sp)  */
        *a++ = 0xa71e0020;              /*  ldq t10,32(sp)  */
        *a++ = 0xa73e0028;              /*  ldq t11,40(sp)  */
        *a++ = 0xa51e0030;              /*  ldq t7,48(sp)  */
        *a++ = 0xa6de0038;              /*  ldq t8,56(sp)  */
        *a++ = 0xa6fe0040;              /*  ldq t9,64(sp)  */

        *a++ = 0x23de0080;              /*  lda sp,128(sp)  */

        /*  Load PC from the cpu struct.  */
        *a++ = 0xa4d00000 | ofs_pc;     /*  ldq t5,"pc"(a0)  */

        *addrp = (unsigned char *) a;

        switch (itype) {
        case CALL_ERET:
        case CALL_BREAK:
        case CALL_SYSCALL:
                break;
        default:
                bintrans_write_pc_inc(addrp);
        }

        return 1;
}


/*
 *  bintrans_backend_init():
 *
 *  This is neccessary for broken 2.95.4 compilers on FreeBSD/Alpha 4.9,
 *  and probably a few others. (For Compaq's CC, and for gcc 3.x, this
 *  wouldn't be neccessary, and the old code would have worked.)
 */
static void bintrans_backend_init(void)
{ 
        int size;
        uint32_t *p;


        /*  "runchunk":  */
        size = 256;             /*  NOTE: This MUST be enough, or we fail  */
        p = (uint32_t *)mmap(NULL, size, PROT_READ | PROT_WRITE | PROT_EXEC,
            MAP_ANON | MAP_PRIVATE, -1, 0);

        /*  If mmap() failed, try malloc():  */
        if (p == NULL) {
                p = malloc(size);
                if (p == NULL) {
                        fprintf(stderr, "bintrans_backend_init(): out of memory\n");
                        exit(1);
                }
        }

        bintrans_runchunk = (void *)p;

        *p++ = 0x23deffa0;              /*  lda     sp,-0x60(sp)  */
        *p++ = 0xb75e0000;              /*  stq     ra,0(sp)  */
        *p++ = 0xb53e0008;              /*  stq     s0,8(sp)  */
        *p++ = 0xb55e0010;              /*  stq     s1,16(sp)  */
        *p++ = 0xb57e0018;              /*  stq     s2,24(sp)  */
        *p++ = 0xb59e0020;              /*  stq     s3,32(sp)  */
        *p++ = 0xb5be0028;              /*  stq     s4,40(sp)  */
        *p++ = 0xb5de0030;              /*  stq     s5,48(sp)  */
        *p++ = 0xb5fe0038;              /*  stq     s6,56(sp)  */
        *p++ = 0xb7be0058;              /*  stq     gp,0x58(sp)  */

        *p++ = 0xa4d00000 | ofs_pc;     /*  ldq     t5,"pc"(a0)  */
        *p++ = 0xa0f00000 | ofs_n;      /*  ldl     t6,"bintrans_instructions_executed"(a0)  */
        *p++ = 0xa5100000 | ofs_a0;     /*  ldq     t7,"a0"(a0)  */
        *p++ = 0xa6d00000 | ofs_a1;     /*  ldq     t8,"a1"(a0)  */
        *p++ = 0xa6f00000 | ofs_s0;     /*  ldq     t9,"s0"(a0)  */
        *p++ = 0xa1300000 | ofs_ds;     /*  ldl     s0,"delay_slot"(a0)  */
        *p++ = 0xa5500000 | ofs_ja;     /*  ldq     s1,"delay_jmpaddr"(a0)  */
        *p++ = 0xa5700000 | ofs_sp;     /*  ldq     s2,"gpr[sp]"(a0)  */
        *p++ = 0xa5900000 | ofs_ra;     /*  ldq     s3,"gpr[ra]"(a0)  */
        *p++ = 0xa5b00000 | ofs_t0;     /*  ldq     s4,"gpr[t0]"(a0)  */
        *p++ = 0xa5d00000 | ofs_t1;     /*  ldq     s5,"gpr[t1]"(a0)  */
        *p++ = 0xa5f00000 | ofs_t2;     /*  ldq     s6,"gpr[t2]"(a0)  */
        *p++ = 0xa7100000 | ofs_tbl0;   /*  ldq     t10,table0(a0)  */
        *p++ = 0xa7300000 | ofs_v0;     /*  ldq     t11,"gpr[v0]"(a0)  */

        *p++ = 0x6b514000;              /*  jsr     ra,(a1),<back>  */

        *p++ = 0xb4d00000 | ofs_pc;     /*  stq     t5,"pc"(a0)  */
        *p++ = 0xb0f00000 | ofs_n;      /*  stl     t6,"bintrans_instructions_executed"(a0)  */
        *p++ = 0xb5100000 | ofs_a0;     /*  stq     t7,"a0"(a0)  */
        *p++ = 0xb6d00000 | ofs_a1;     /*  stq     t8,"a1"(a0)  */
        *p++ = 0xb6f00000 | ofs_s0;     /*  stq     t9,"s0"(a0)  */
        *p++ = 0xb1300000 | ofs_ds;     /*  stl     s0,"delay_slot"(a0)  */
        *p++ = 0xb5500000 | ofs_ja;     /*  stq     s1,"delay_jmpaddr"(a0)  */
        *p++ = 0xb5700000 | ofs_sp;     /*  stq     s2,"gpr[sp]"(a0)  */
        *p++ = 0xb5900000 | ofs_ra;     /*  stq     s3,"gpr[ra]"(a0)  */
        *p++ = 0xb5b00000 | ofs_t0;     /*  stq     s4,"gpr[t0]"(a0)  */
        *p++ = 0xb5d00000 | ofs_t1;     /*  stq     s5,"gpr[t1]"(a0)  */
        *p++ = 0xb5f00000 | ofs_t2;     /*  stq     s6,"gpr[t2]"(a0)  */
        *p++ = 0xb7300000 | ofs_v0;     /*  stq     t11,"gpr[v0]"(a0)  */

        *p++ = 0xa75e0000;              /*  ldq     ra,0(sp)  */
        *p++ = 0xa53e0008;              /*  ldq     s0,8(sp)  */
        *p++ = 0xa55e0010;              /*  ldq     s1,16(sp)  */
        *p++ = 0xa57e0018;              /*  ldq     s2,24(sp)  */
        *p++ = 0xa59e0020;              /*  ldq     s3,32(sp)  */
        *p++ = 0xa5be0028;              /*  ldq     s4,40(sp)  */
        *p++ = 0xa5de0030;              /*  ldq     s5,48(sp)  */
        *p++ = 0xa5fe0038;              /*  ldq     s6,56(sp)  */
        *p++ = 0xa7be0058;              /*  ldq     gp,0x58(sp)  */
        *p++ = 0x23de0060;              /*  lda     sp,0x60(sp)  */
        *p++ = 0x6bfa8001;              /*  ret   */


        /*  "jump to 32bit pc":  */
        size = 128;     /*  WARNING! Don't make this too small.  */
        p = (uint32_t *)mmap(NULL, size, PROT_READ | PROT_WRITE | PROT_EXEC,
            MAP_ANON | MAP_PRIVATE, -1, 0);

        /*  If mmap() failed, try malloc():  */
        if (p == NULL) {
                p = malloc(size);
                if (p == NULL) {
                        fprintf(stderr, "bintrans_backend_init(): out of memory\n");
                        exit(1);
                }
        }

        bintrans_jump_to_32bit_pc = (void *)p;

        /*  Don't execute too many instructions:  */
        *p++ = 0x205f0000 | (N_SAFE_BINTRANS_LIMIT-1);  /*  lda t1,safe-1 */

        *p++ = 0x40e20da1;              /*  cmple t6,t1,t0  */
        *p++ = 0xf4200001;              /*  bne  */
        *p++ = 0x6bfa8001;              /*  ret  */

        *p++ = 0x40c01411;              /*  addq t5,0,a1  */

        /*
         *  Special case for 32-bit addressing:
         *
         *  t1 = 1023;
         *  t2 = ((a1 >> 22) & t1) * sizeof(void *);
         *  t3 = ((a1 >> 12) & t1) * sizeof(void *);
         *  t1 = a1 & 4095;
         */
        *p++ = 0x205f1ff8;      /*  lda     t1,1023 * 8  */
        *p++ = 0x4a227683;      /*  srl     a1,19,t2  */
        *p++ = 0x4a213684;      /*  srl     a1, 9,t3  */
        *p++ = 0x44620003;      /*  and     t2,t1,t2  */

        /*
         *  t10 is vaddr_to_hostaddr_table0
         *
         *  a3 = tbl0[t2]  (load entry from tbl0)
         */
        *p++ = 0x43030412;      /*  addq    t10,t2,a2  */
        *p++ = 0x44820004;      /*  and     t3,t1,t3  */
        *p++ = 0xa6720000;      /*  ldq     a3,0(a2)  */
        *p++ = 0x205f0ffc;      /*  lda     t1,0xffc  */

        /*
         *  a3 = tbl1[t3]  (load entry from tbl1 (whic is a3))
         */
        *p++ = 0x42640413;      /*  addq    a3,t3,a3  */
        *p++ = 0x46220002;      /*  and     a1,t1,t1  */

        *p++ = 0xa6730000 | ofs_c0;     /*  ldq a3,chunks[0](a3)  */

        /*
         *  NULL? Then just return.
         */
        *p++ = 0xf6600001;      /*  bne     a3,<ok>  */
        *p++ = 0x6bfa8001;      /*  ret  */

        *p++ = 0x40530402;      /*  addq    t1,a3,t1  */
        *p++ = 0xa0220000;      /*  ldl     t0,0(t1)  */

        /*  No translation? Then return.  */
        *p++ = 0xe4200003;      /*  beq t0,<skip>  */

        *p++ = 0xa4700000 | ofs_cb;     /*  ldq t2,chunk_base_address(a0)  */

        *p++ = 0x40230401;      /*  addq t0,t2,t0  */
        *p++ = 0x6be10000;      /*  jmp (t0)  */

        /*  Return to the main translation loop.  */
        *p++ = 0x6bfa8001;              /*  ret  */
} 
